I've been using my P5W DH since I was in 7th or 8th grade. I forget when I exactly built it. I am now a rising junior in college and out the the PC scene. I mainly use my desktop for racing simulations. It is slow at this point, and I have 50/50 on upgrading a little (to a Q6600) or a lot (mobo/CPU/RAM). Any advice?

P5W DH Deluxe
E6300 (Conroe?)
Corsair 4gb (2x2GB)
ATI 5870
Seagate 160GB 7200RPM
Corsair TX750

Win7 Home Premium 64-bit