Upgrading

Hey been coming to the site for awhile and im really getting into computers and i have a question. I have a Hp pavillon a6628f computer. http://h10025.www1.hp.com/ewfrf/wc [...] ct=3813352 its got a 9300ge graphic card in it now and it seems that it draws all its power from the pci slot itself. and i was wondering if you could recommend a new card that also draws the power from the slot since its only a 300 wat psu. on the psu it shows these #'s

input 100-127v-8a 200-240v 4a 50/60hz

output 12v / 19amps -12 /.8a

300w max +5v /25amps 5vsb /2a

3.3v/ 18amps

+5v & +.3.v 175w max +5v & +12v 268w max

we mostly watch movies since it has a blue ray player in it (on a 25inch lcd right now) and light gaming but really nothing new mostly older games and we want to be able to run it on a bigger screen and try some of the newer games (mostly the new starcraft and diablo that will be coming out) Or do you think a new psu would still be in effect with any card we choose. Keep in mind though a noob with comps but trying to learn. (and would llike to stick with nvidia and the tower isnt very big but looks like only thing i would lose with a bigger card would be a pci-e port but its no biggy)