brand new rabbit alternator gone

i just recently purchased a 2008 vw rabbit and i put a system of 2 alpine type rs and the amp that goes along .  its 1000 watts rms power which has been putting a strain on my alternator and all my lights are blinking and all that good stuff and today the battery light finally went on so i think my alternator is gone due to overload.  is there any sites where i can get a stock alternator for cheap.  the cheapest i've found is 300.00 dollars .. if you could reccomend a place that would be very helpfull.
thanks,
tim

whoa!!  don't need alternator, go to best buy, circuit city, or speaker store and get yourself a 1 ferrod capacitor.  It stores battery power in it, doesn't let your lights dim, and helps power the system and not put a load on all your electrical.  It wires into the same circuit as the amp.

i am going to buy one but my battery light is already on.  so therefore i think its either my alternator or maybe my battery is just shot.  so can you give me your opinion.  

so your battery isn't getting charged?  Take it to like autozone or another parts store that does free testing and they will tell you.  I'd rather change battery then alt but I don't want to tell you to change the wrong thing.  If you're battery keeps dying then it would def be the alt.

i tested it myself today and i figured out that its my alternator ... by me putting subs in it does that void my warrenty?