Can AC fan or motor be upgraded

If both your central air handling fan and outdoor compressor are running and your not seeing any sort of cooling after a 10-20 minutes than I'd venture a guess and say it's time to call an AC repair service.

I'm curious what you are pushing in that makes the compressor turn on? Are you somehow bridging the main capacitor? Capacitors tend to be a common point of failure on AC units and can actually be changed fairly easily. Here is a pretty good article detailing the steps to do so.

To be honest though I'd guess that the bigger problem is the fact that you can get it running and it still isn't putting out cold air. The whole situation sounds like it's low on coolant (have you had it filled in the last few years?). AC's usually have a low coolant pressure switch that will keep the unit from running to prevent damage to the compressor when there isn't enough pressure.

Call an AC service out, many will diagnose your problem free of charge and be able to give you a much better idea of your problem. Be warned though, if your system is old and uses R-22 prices have shot up in the last year.

Check your start / run capacitors. They live in the outside unit, near the switch.

They look like oval or circular cans, and they feature prongs on one end and a flat bottom on the other. If either end looks even remotely non-flat, the capacitor has failed and the compressor won't run (even if there's freon in the line and the compressor is functional). Sometimes there is only one capacitor, as it has both the "start" capacitor and the "run" capacitor built into the same package.

If you are in doubt as to the "flatness" of the package, pull the disconnect near the outside unit, provide a bit of time to let the capacitors drain (10 min should be sufficent) and pull the capacitors out of the system (take care to identify the wiring, wiring a capacitor backwards is not recommended). Then find a nice flat table and if one wobbles, it is gone. If it is flat on the table, you dont't have this problem.

The repair (if needed) is a new capacitor ($10 to $15 at an AC parts supplier, no license needed for this part). If you find these capacitors failing more often than "once in a blue moon" it is a strong indication that something else is wrong with the system, like worn windings on the compressor motor, or possibly an electrical short elsewhere.

You can replace a two-in-one capacitor with two single capacitors (provided they match the original ratings) and vice-versa. But there's no need to get all fancy.

And everyone says "low freon" or a compressor. Get used to it. Occasionally they are right, but a failure like that sounds odd if recent repair work was done, unless the repairman did a shoddy job.