Hey , check out the first post. Theres links and instructions for overclocking and download links for the tools you need. Sounds like you haven't done much overclocking in the past and that's okay, we can help.
First off, does your 7950 have a 6+8pin power connector(s) or 6+6?
Also, don't use Overdrive in CCC, it sucks. Period.
Follow the guide a little bit and come back and let us know how it goes, also, try to simply keep your voltage where it is and increase the core frequency and keep testing it until its unstable, find your stable point, and then increase the memory slowly until instability. Increase the voltage by 5-10mv and then find your stable frequencies again.
The card is rated for a safe operating voltage of 1.25v. You'll max out well before 1.25v on the TFIII, and your temperatures will be high anywhere past 1.2v. Let us know how it goes, i can help "plug" in numbers for you that i'm running and we can tweak em to work for ya. Every card runs/overclocks differently.