Forget the 6850, AMD newer drivers dont do anything really for pre-7000 series. Grab the GTX 460 if its the 1gb, 336 core version. The 6850 and GTX 460 are equal performance wise. But really I would grab a more modern gpu series like the GTX 750 or AMD's R7 260x. Also I would do the tape mod on the cpu to bring that Q6600 to 3ghz. Depending on your resolution a GTX 460 will allow mostly high settings.