I'm using the same card myself.
My settings are as follows:
cgminer.exe --scrypt -I 15 --thread-concurrency 25614 --gpu-powertune 20 --temp-cutoff 90 -o [URL] -u [username].[worker, if necessary] -p [password, sometimes whatever]
I'm still experimenting with what works best, so my settings will quite possibly (if not probably) be less than optimal. The intensity is also set lower because I'd also like to be able to use that computer at the time, which is nearly impossible at an intensity of 19 or 20 (which I've found it what quite a few people with 7950s use as their intensity).
[Edit] Added more information and formatted settings into code tags.