Black Hawk

Hello I have a 1999 Pontiac Trans-Am and I've been having some energy problems for a while now. The lights would surge as well as the AC and the volt meter drops considerably. Started it up yesterday and I could here a whining noise coming from the engine comp, popped the hood and the noise is coming from the alt. So I'm looking to purchase a knew one, also is there anything else I could change while I'm working in that area (belt, the car is completely stock except for battery, tires, and filter).

This one seems like a good part:

http://www.autopartswarehouse.com/pe...1&brandid=4277

I've also thought about purchasing a GM one, but for the price their selling it for I might as well buy this one:

http://www.autopartswarehouse.com/pe...1&brandid=2506

Any input is appreciated