Almost anything will be faster than your onboard xpress 200. Depending upon what your doing with the GPU, you could get a low profile card that required no external power.
The card I'm thinking about (MSI N9500GT-MD512/D2 because it's less than $40) says it recommends a 350W PS minimum. I currently only have a 300W in my system. Is it worth just buying the card and trying it out or is this something that can trash my PS or make my system unstable. I do know that my mobo is only pcie 1.0a compliant so I know that the card won't be utilized to its max performance. Perhaps this helps with the power consumption.