Alternator questions

My dash lights warning lights lit up last night so I figured that the alternator is dead. On the way home, I noticed that my lights were getting dimmer and dimmer. Advance Auto Parts only lists a 70 amp alternator at their store, but on the website they have a 80 amp Worldwide, Autolite- unknown amperage, and a 110 amp Bosch. I suppose that the first 2 are out- and that my only choice is the Bosch. But while searching the internet for cheaper prices (since I have to order it anyway...), I saw a voltage regulator listed here http://64.15.251.33/cgi-bin/sewse?/u...2p.cmm+discap2 . Anyway, I want to know where might this voltage regulator be on my car, and if it is a possible culprit. I saw the Bosch listed at Drivewire.com cheaper than Advance.
http://catalog.drivewire.com/drivewi...art=Alternator

BTW my car was making a whistling/growling noise the day before the dash lights came on. I could have the alternator rebuilt, but the guys that will do it never have the stuff for foreign cars in stock so you have to wait a day o two to get the parts. But they have an 30 or 90 day warranty I think... What do you guys think?

Thanks,
Kelly