RPM problems

I have a 1994 Camry DX, 2.2L. I have a couple RPM problems. First: When the car is first started the RPM is at 1000 while in park, after driving for a while and the car is warmed up the RPM is at 1200 in park. Second: When the air conditioning is turned on the RPM drops and the car almost stalls. What could be causing these problems and what's the fix. Thanks.