Heater

1993 cheny lumina car 140,000 miles 3.1 engine automatic my car never fully heats up it can sit and idle for an hour. When you get in my car it is luke warm on the inside when you move the car it cools down very rapidly in the car I don't know why please help me I have never done any work to the heater and my air conditioner does not work either please tell me how to six this problem before it starts getting cold out again