Like said before by those guys...
better to start from scratch
Keep everything except: mobo, RAM, proc and GPU
Recommended proc upgrade: i5 3570k or FX8350 (no need to go i7 unless if you really need it or badly want it)
Recemmended chipset: Z77 or 990FX
Recommended RAM: 8 or 16GB DDR3 1600
Recommended GPU: at least HD6850...directly go for 2 of them if you want...
You can either go directly for all (mobo, proc, ram, gpu) or divide the items in 2 steps (the order is your decision): 1. mobo, proc, RAM and 2. gpu...if you are short of budget
Optional: dump the 60GB 10k rpm and get yourself a fresh new at least 128GB SSD.
I would rather keep your Q6600 (perhaps OC a bit) and go for GPU only at the moment and wait for Hasswell.
Q6600 is not that bad.
I am now preparing my budget to replace my Q6600, P5E X38, HD6850 and 6GB RAM early next year...it looks like that I will skip sandy bridge and go for Hasswell...or perhaps something newer at that time...also skip HD7xxx series...go for something better next year...