93 VR6 rough idle/acceleration when warm

Wondering if anyone knows how to solve this problem...

Have a 93 VW Passat VR6 with an AT. When I start it, it idles fine and seems to drive fine. Once the engine warms up tp running temp it idles rough. It will idle normally for a few sec, then the RPMS will drop, vibrate the car, then kinda bounce up and down for a while. Also, sometimes when accelerating i'll give it gas and the engine will almost die for a second, then it will go back to normal. It definitely seems worse when the outside temp is higher, as it wasn't that bad during the winter, and alot worse now as its getting warmer outside. Also, the car seems to be running hot. In traffic, the gauge will hit close to the 230 mark, not sure if this is normal.

One more thing, I know this may be a general automotive question.. My air conditioning is not working. When I turn it on, i can hear it turn on, and feel the power loss, but no cold air comes out. I've seen those a/c recharge units in the store, is this a possible solution??

Thanks