If you can get into Bios, then your able to overclock. I think that is what gurusan meant.
If you OC this thing to 3ghz, then if you want to, stay with what you have now and save up for a better rig ($1,300+?).
Or if you get it to 3ghz, just sell your 8600gt for however much you can and then buy an 8800 GT. I really doubt your going to max AoC out with only $500 anyway.