You can do better than the Alpine R-Type for it's price. I am the CEG's resident Alpine whore, so please don't take this as bashing. I would suggest
http://www.stryke.com/SAL-PB12.html They are the best subwoofer you can buy at thier price point.
As for the Alpine amps, I have one of the older V12 models, the MRV-T757, and althogh it has given me a year of problem free service and sounds great, I still believe that for the same ammount you could do better.
Look into an older PPI amplifier, ar an a/d/s, they will be expensive for used amps but there is a reason for that. You obviously have a computer so Ebay would be the place to look