no need for a GTX 560Ti or HD 6950 as long as you're playing at this resolution, HD 6850 or GTX 460 will get the job done.
getting HD 6950 now is not worthy, as the HD 7K series new XDR2 rambus technology is said to be twice faster than GDDR5 besides 1 GHz GPU frequency, 28nm process = less heat, less power consumption
Well I can say this after owning two 9800gt 1gb and a 8800gt. I am a collector of cards and also have a gtx 460 1gb. It takes two 9800gt in sli to even get to the performance of a single stock gtx 460 so if it is on par with a gtx 460 you will see a massive boost in overall performance.