The magic item you're thinking of is probably the Potion of Regeneration. The level 9 version costs 160 GP a pop and gives you regeneration 5 while you're bloodied. It also costs a healing surge, which might be a problem for your wizard if you do a lot of encounters in a typical day.
Trollhide Bracers have a daily that also gives you regeneration 5, not just while you're bloodied, but those are a level 19 item so it'll be a while before you might have those.
Armor of Sudden Recovery is great for regeneration. You can, as a daily, convert any ongoing damage you're taking to regeneration -- so if you're taking ongoing 10, you can turn it into regeneration 10. I would strongly recommend a set. A slightly cheesy but amusing option: combine that with Dragonfire Tar, an alchemical consumable which does ongoing damage on the target. Use that on yourself. Check with your GM before using this one, though.
Back to non-cheese. For your neck slot, an Amulet of False Life has a daily that gives you temp hit points equal to your healing surge value. That's effectively an extra second wind once per day. I think that's better than the Amulet of Life, which allows you to spend an extra surge once per day when you spend a surge, since you have to wait for someone to heal you or use second wind with the Amulet of Life.
Diamond Cincture is another effective second wind, once per day. So that's pretty good. It fills your waist slot.
OK, let's see. Strategies -- don't forget about Shield. That's a very good defensive utility. With any luck it'll prevent one hit per encounter. For your level 10 utilities, you have a few interesting choices. Mass Resistance is a life saver if you're fighting anything at all elemental. It's party-oriented, which is nice. Blur is a great power to protect you -- you can't be seen by enemies more than five squares away, plus you get some defensive bonuses. If you have some way to fly, which you probably will eventually, this is a great way to stay safe in the air.
Points of Light
Yes, it does. It’s called “Points of Light,” and my understanding is that it’s basically Greyhawk (Gary Gygax’s original setting for Dungeons & Dragons) with the Gygaxian serial numbers filed off so Wizards can avoid paying them royalties, or something like that.
The core books use this setting. Most supplements use it too, though for the most part they strive to be generic enough to be reasonably added to many different types of settings.
I want to include a quote here by BESW, originally made as a comment to this answer, because I think it’s particularly relevant:
I think it's worth mentioning that the Points of Light setting is deliberately fuzzy on the details. IE, yes, there was a war between dragonborn Arkhosia and tiefling-led Bael Turath a long time ago, but whether that's a thousand or five thousand years ago depends on which article/book you're reading. This is done to take some of the "get it right" pressure off the DM and discourage players from telling the DM that his worldbuilding choices are wrong.
This is one of the better ideas that Wizards has ever had, in my opinion, and you should feel free not to worry too much about matching your campaign up with the “official” details. This was always true, even in the more well-defined settings, but a lot of DMs, especially new ones, felt like they had to match everything perfectly.
Setting Specific Material
The only supplements that don’t use Points of Light, appropriately enough, are the setting-specific books, like books for Eberron or the Forgotten Realms (Faerûn is a part of the Forgotten Realms). There’s not any particular reason why you have to avoid the material from those books in other settings, mind you: they may have been written with a particular setting in mind, but that doesn’t mean you can’t incorporate them into other settings.
For example, the Artificer is kind of the iconic Eberron class, but while Eberron is largely built on the backs of Khorvaire’s Artificers, there’s nothing saying that the Forgotten Realms couldn’t have a fair few Artificers walking around. They’re just not quite so ubiquitous as they are in Eberron, so you haven’t seen the magitech-ish revolution in the Forgotten Realms the way you have in Eberron.
As another example, Dragonmark feats are balanced socially rather than mechanically for their intended setting: getting a 4e Dragonmark means you're socially obligated (or being hunted by people with social obligations re: Dragonmarks) and have effectively handed the DM a "tug my PC around" card. Outside of that social context, Dragonmarks are a little overpowered mechanically (read: nearly on par with Expertise in terms of "why doesn't every PC have one of these?”) without extra work by the DM.
The only setting that really doesn’t play nice with others is Dark Sun. Dark Sun changes a lot of the core assumptions about the world, and a lot of Dark Sun material exists to support those different assumptions. It’s been important to Dark Sun, for a long time now (at least since 2nd edition), that it’s completely cut off from any wider cosmology (in 2e and to a somewhat lesser extent 3.x, all settings were generally sub-settings within Planescape, at least from Planescape’s point of view). Again, though, that does not mean you cannot mix Dark Sun with other settings – it just means you have to be more careful about it.
Pantheons
For the most part, the pantheons are separate, though if I recall correctly, Points of Light and the Forgotten Realms have a fair bit of overlap. Eberron’s gods and the like are certainly completely separate, and Dark Sun... only kind of sort of has gods at all.
Changelings
I don’t know of any particular mention of Changelings in the Forgotten Realms or any place where Changelings are explicitly included in the setting, but they’d hardly be out of place if you wanted to include them.
Best Answer
You are correct that you are not proficient with shields, so carrying around a shield will not help you unless you pickup that proficiency from somewhere else.
What the ability means is that you get a +2 bonus to your AC. The type of bonus is a shield bonus, which means it won't stack with other shield bonuses to AC (you get whatever the largest is), but it will stack with feat or power bonuses. This bonus is granted by the class feature, and does not require you to have a shield.