2005 Pontiac Grand Am alternator

Power steering fluid leaded in to the aleternator. Two months ago at a car wash the car stalled and needed jumped. Tonight it was acting up again. At a stop light the car would almost stall. The tach. Woudl drop to 0, the head lights and dash board lights would dim or go out, the radio would "buzz", and the air bag and low fuel lights would go on. It only happened when the brake was pushed. I tried putting it in neutral and revving the engine and that worked. I got home shut it off, then turned it back on and drove around the block and now it is working fine. Also there was smoke and a burning smell coming from the area of the alternator.
Do I need a new alternator or can this be repaired?