Graphics Card for Asus Motherboard 300w power supply

I have a

HP Pentium Duo Core e5300 @ 2.6 ghz
Asus Motherboard Name: IPIBL-LB
HP/Compaq motherboard name: Benicia-GL8E
6 Gigs RAM
Vista 64 bit
integrated graphics card
300 w power supply

The motherboard supports one PCI Express x16 Graphics Card

Want to drop in a reasonably price graphics card without changing the 300 w power supply.

Probably will play Everquest (when I have the time again) and the occasional new game. (i.e. Just bought
Bioshock and it won't even load)

Most of the time though will watch video and check emails. Nothing graphics intensive. (Other the Bioshock, read about it a few years back and have been wanting to play it)

Can you suggest something.

Much appreciated.