As others have said, the GTX 460 768 MB version would be a great card for your setup. They can usually be found for under $200 CDN and it should max most games at 1280x1024. If you don't want that card, then the 5770 is also great bang for your buck.
GTX 460 Review:
Link: NVIDIA Quote:
Originally Posted by fishingfanatic For new cards you'll want at least a good 500 watt psu. I would recommend a Corsair 520 at the minimum. The 460 is a great card, the 1gb version would be great as well from EVGA.   |
I don't think the OP would run into any problems with a quality 400 or 450 watt unit. Corsair CX-400 should handle a 5770 or GTX 460 fine.