at that resolution a 5670 should do well yes
the problem in your search is the perfect nvidia card for you is a gts 440 but nvidia decided to only sell 440's to oem.
they have a hoel in thier lineup, you fall into that hole unfortunatly
the 5670 is not a powerful card, btu really at 1024 x 768 you don't need that much power. 5670 is the best option you have unless you're willing to sacrifice dx11