My air doesnt work

I am a little confused as to what exactly you are asking for help with. You are saying that your Air Conditioner doesn't work, but your heater does? And the engine is over heating?

The engine overheating could be caused by low coolant in the radiator, a faulty thermostat, or worse case a bad water pump. I'd check the fluid in the radiator (when it's cool) first and top it off with 50/50 mix of the same color as already in there (green with green, orange with orange, etc.)

If it is the thermostat (the next cheapest repair) I would have a service shop tackle that. If you want to try yourself, you might want to invest in a repair manual for your car.

If it is not any of the other two problems, it may be a broken or worn water pump (most expensive of the 3). This is a repair for an experienced mechanic and not for the novice. I am not sure of your skill level, but if you're willing to give it a try, you should definitely get a repair manual like, chilton or hanes. They'll show you step-by-step, with illustrations, how to replace it.

Without seeing the vehicle, or knowing the exact make, model, year, engine size, etc. it is very difficult to figure out exactly what's wrong.