2004 Saturn Ion air and acceleration problem

I want to know what do I need to do to fix my 2004 Saturn ion
when sitting at a redlight with my foot on the brake my car will accelerate on its own. At the same time this started my a/c started only blowing cold air while driving and when im sitting still it blows warm air the temp of the air that day I don't know if this is two separate problems but am wondering if it is due to the fact that the air gets colder due to acceleration of the car and when sitting still the air blows hot and the car accelerates on its own.