Toyota Camry 1996 is running odd?

I have 1996 camry (2.2 automatic) and have literally replaced all the parts except for the transmission and alternator. Lately, the car has been running a little weird, I got a tip that it could be the alternator, as was i was thinking, and decided to look it up and found that the grounding was very dirty so i cleaned it off with some carborator cleaner and a tooth brush. the vehicle ran great this morning but on my way home, i turned on the a/c had the radio going and was rolling my windows up when i noticed they were rolling up awfully slow. then my car starts to display my time very dim and the radio starts going in and out and finally the car starts puttering. luckily i made it home in time before it just shut down totally and the engine had gone off as well. im hoping the connection is just loose but im not sure if i want to trust my opinion solely here as i have quite a commute tomorrow and was curious if anyone could tell me what else it might be....im figuring the alternator may need to be replaced...no big deal, its right in front but might it not be replaced and save me 150 bucks? thank you!!!!