My tbiuron overheats in stop and go traffic, especially when using the air on 1997 Hyundai Tiburon

It it cools down when the heater is turned on to high.
Also, the sound on my radio speakers went out. First on the right chanell and not the other one is out.
It started to sound bad with bad treble,having to turn down the treble level to its lowest setting and then sounded better after driving a while.
Just had alternator repalced.

Asked by for the 1997 Hyundai Tiburon