What card can I run with only the power from the motherboard

Ok, so my computer died and I am unable to replace it. Luckily my brother in law is in charge of tech disposal for his company and gave one of their outdated ones. It is still a good system and runs fine but it is also energy star rated and the power supply doesn't have any cords for a video card. Currently I have an old nvidia f5500 256mpg in there and it works ok with the settings on low, but I would like to get something better. I do have my gforce 8800 gts but since it requires additional power I can't use it (or can I?).

Any suggestions for a, low cost, better card?

Thanks,
Mark

You can also change the power supply, 40$ you can get a corsair with all you need. You can tcheck for card like the 450gts or something like that low end card but can run gw on high. Use Ncix.Com to see what you can use plenty of cgoice

I went to the Nvida site and it recommended the GeForce 610 galaxy, it has a lot of positive reviews so I think I will get that one.

Thanks
Mark