As far as the AC goes, check to see if it has pressure. You can buy a guage at autozone for like 15$, it screws on easily. If you have no pressure, charge it. Takes 5 min of holding a button down, extremely simple. Then see if it holds the charge for a day. If not, your o-rings are likely shot. It gets a bit more involved at that point, but if you get that stuff done, it may fix the problem, but at the very least it'll give you the general layout of the engine bay.
To check the pressure of the line, open the hood. Not far from the battery there is a metal hose running front to back of the car direction, about 3/4" diameter, and there's a blue cap. If you remove the blue cap, it'll have a place for you to hook up the nozzle. I bought this one:
You'll notice that it has the guage built in-line, with a "Low, Good, High, and Danger" color areas. If you fill to much, you can bleed the line without a problem. Which ever can you get, just be sure to read the instructions on the back, they're fairly simple and strait forward.
Good luck.