Saturn Repair: Alternator, lifetime warranties, decent warranty

Question
I have a 1996 Saturn SL1.  I think I know what the problem is, but I'm asking anyway.  The battery light came on this morning.  For the two days prior to this, the car has been making a high-pitched whine, not a squeal like a belt would make, but a whine.  Today, when I stopped at a red light, the temperature gauge kept dropping to cold and then climbing back to where it's supposed to be.  The radio was fading in and out, too.  Can you give me an idea of how much it should cost to replace the alternator?  Will I also have to replace the battery?  Thanks!

Answer
Rebecca,
 You can usually find an aftermarket alternator at one of the big-name parts houses (with a decent warranty) for around $75-$100.  Labor on that job should run about the same, maybe a little higher.  You should not have to replace the battery  but you should at least have it checked.  You can also find aftermarket alternators with "lifetime" warranties.  This is a good idea due to the fact that they WILL fail again, it's only a matter of time.

Chris