Your noise is definetly the alternator, I had the same exact problem. I have 154k miles. I don't know how long yours will last...it could be 6 days or 6 months. My lights started occaisonally pulsating and the battery light would come on when the engine was revved high, so I knew its time was up. I was quoted $430 from Midas to replace it so I did it myself. I found a brand new one on EBay for $140 shipped and threw it in myself, only took about 2 hours with my helms manual. Would've taken half that if I had had power tools. I should've taken pics while I did it for a DIY but I forgot

If you want to do it yourself and need help hit me up on AIM, PM or email...it's a very easy procedure, just takes some work. I'll take some pics of my Helms manual, I think it's 6 steps long. Anyone can do it themselves, plus it's one of those things that's nearly impossible to screw up.

edit: you should hear the whining noise when you're driving around too. Maybe you're not as in tune with your car as I am or maybe your noise isn't as loud, but mine sounded like a supercharger and the noise was prevalent up until about 3k RPM.