If u have the right ram, harddisk, and good video card(which seems like u do) u can upgrade ur comp for about 200 bucks.. get a good motherboard and cheap-and-good processor.
check www.googlegear.com they are pretty nice.. but don't buy the monitor there.. i got my viewsonice monitor ripped off a bout 50 bux
you want stability and best performance for intel, get an Intel chipset. right now I'd recommend Springdale, or possible Canterwood, if you're a performance junkie.
Oh really!?... I find my SiS chipset board to be extremely stable...Intel roxorz, but SiS is better than mediocre in my opinion...or at least when its on an Asus board.