This is a pretty interesting question. Without more clarity as @mxyzplk points out, I'll keep this at general suggestions, but I'll be happy to add more clear suggestions later if necessary.
First off, let's look at your ability scores. Your Cha 20 is going to be netting you +2 additional 1st level spells per day, which gives you a total of 5 (I'm going to leave 0th out of the answer, since they're however many times you want). Problem with Oracles is they get 2 1st level spells known per day at 1st level which if I'm not mistaken can't be modified by anything. This is also going to make the saving throw target number for your 1st level spells 16 (10 + Cha bonus of 5 + Spell level 1), which isn't too shabby.
Your Revelation makes your Cha bonus apply to your AC instead of Dex, and adds to your reflex save. You're going to be decently hard to hit, with a +5 bonus to your AC and reflex.
The rest of your abilities, though, cap out at a +1 bonus. So base, you're at a +1 to hit in melee (+0 BAB for starting Oracle), and a +0 for Ranged.
You're getting 4 + 1 skill point per level for the Int bonus, +1 for being human (and possibly an additional one if you do that with your favored class, which I'm assuming is oracle). The rest of your stats are +0.
The Lore mystery will play heavily into your skills. You'll be doing a decent amount of skill rolling outside of combat, and will be able to identify magic items with the best of them. Plus, being able to Brain Drain a captive to get information is just cool.
The Trickier bit is going to be combat. Here are a few suggestions to get you started:
Buff/Debuffer
Okay, so here's where we can branch out a little. My primary suggestion would be (depending on the composition of your party) do something with buffs/debuffs. Bless is a nice 1 min/level spell that gives every ally within 50 ft a +1 attack bonus and a +1 to fear saves. Couple that with your high-ish spell save DC and you could take Bane,Cause Fear, or Doom for a bit of early-on battlefield control. Your High Cha will give you a decent save DC, and additionally your AC will be pretty decent for your class. Also since you can Spontaneously cast Cure Spells whether or not you know them, you're a decent support healer in a fight as well. You can also up your Save DC with Spell Focus in the given school your chosen debuff spell is in.
Fighting Route
If you want to go the route of attacking things youself, I would suggest you take Magic Weapon and Shield of Faith (or Bless if you want to up your attack more, it stacks with the Enhancement bonus of Magic Weapon). You can take feats which make you a bit more effective with your chosen weapon (which, base, is limited to simple weapons), but you need BAB of +1 to get Weapon Focus, and you can't get anything past that without being a fighter.
Summoning Route
Alternatively, you could take Summon Monster I and a few feats to boost the effectiveness of the summon (Augment Summoning and it's prerequisite), to dole out some more damage.
TeeHee you can't hit me
If you want to do nothing but dodge attacks, you could: Take a combination of Entropic Shield, Shield of Faith, and Protection from Evil. Note that the AC bonus of Shield of Faith and Protection from Evil don't stack, since they're both deflection, but you get the idea. Nothing like a 20% miss chance from ranged attacks and a 20 AC at 1st level (+4 from armor, +4 from Cha, +2 from Spell). If you consider upping your Dex to 13 at the cost of say your Con, you could take Dodge as a feat, get another +1 to your AC, and then make up for the loss of a hit point per level with your favored class bonus.
Per your Metamagic Feat suggestion, since you're a spontaneous caster, keep in mind that any metamagic feat you take will force you to spend a full-round action casting the spell. (Aside from Quicken Spell, of course).
Oracle is a spontaneous, divine spellcasting class. She has a greater number of spells per day than a Cleric, and can cast without preparing in advance; but, she has a narrower list of spells that she can choose from. She is the divine equivalent of a Sorcerer (whereas a Cleric is comparable to a divine Wizard).
Be mindful that Oracle isn't especially tuned for making ranged attacks (though she isn't terrible); as you level up, if you find that ranged attacks are your focus more than spells, you may want to consider multi-classing into a prestige class that gives you a higher Base Attack Bonus while continuing your spell progression (Eldritch Knight is a good example). On the other hand, you may decide that you want the Oracle's neat higher-level class abilities (Revelations, etc) more than you want a couple points of extra attack bonus.
Abilities:
Key ability: Cha.
Your key Ability score is Charisma, since Cha gives your spells a higher save DC, limits the highest level of spells you can cast, and grants you bonus spells per day.
For ranged combat, you also need a high Dex. Dex also improves your ability to dodge attacks, and increases your Reflex save (resist fireballs, traps, etc).
Con gets you more hit points, and a higher Fortitude save (resist poison, being turned to stone, etc).
Str won't be very important to your character, except to carry gear.
Int grants you more skill points.
Wis gives you a higher Will save (resist mind-affecting spells, etc).
Skills:
Look through the class skills to figure out what interests you. You should have max ranks in the Spellcraft skill. You can also choose cross-class skills without a big penalty in Pathfinder, so you should skim through the entire skill list to see what's available.
As a rule of thumb, I usually pick a number of skills equal to the number of skill ranks I get per level. For example, if you get 8 skill points per level, you could put max ranks in 8 different skills. If you decide you want more skills than that, you can split up one "ranked skill" into two "half-ranked" skills, and put a half-point in each every level. This isn't a hard-and-fast rule, just a way that I've found of making the decisions and the math much easier.
Feats:
The Extra Revelation feat is an Oracle-specific feat lets you choose an additional optional ability from the list for your chosen Mystery.
Since your character is heavily involved with ghosts, I think the Ectoplasmic Spell metamagic feat from Advanced Players' Guide would be appropriate.
Beyond that, feats which enhance your spellcasting will be the most effective for your character; since you are doing ranged combat, you will have to split your feats between ranged and spellcasting. I would recommend reading through the table at the beginning of the Feats chapter (both in the core rulebook and the Advanced Players' Guide) to get a brief description of what each feat does; there are a lot to choose from.
If your group is more familiar with 3.5 than with Pathfinder, remind them that you get a feat every 2 levels, not every 3 (so you should have 3 character-level feats at level 5).
Best Answer
This seems like a reasonably solid build for a Pathfinder Metal Oracle. Here's one way to increase both readiness and damage output.
You said your primary concern is maximizing damage output, and also that you are concerned about surprise attacks and over-reliance on buffing. Things I don't see, which directly address your primary concerns are a reach weapon and the Combat Reflexes feat. Combine these with tactical positioning and get both your martial and spell abilities into action on Round One. My experience shows that this approach will roughly double your damage output through level 9. Maybe this is already your plan, but you don't say so. This would be one way to take this character concept to the next level (pun intended).
Basically, you cast spells with your Standard Action and inflict damage with AoOs. This works surprisingly well in Pathfinder. This historical battlefield combat style is called 'pike-and-shot' and dominated European battlefields for several centuries. This build first became prevalent with Reach Clerics, but the principle of improved action economy also benefits Oracles.
The Combat Reflexes feat is doubly important,because it both gives you iterative AoOs and also lets you take AoOs before your first action, which is especially important in ambush situations.