What are the rest of the computer specs. Is is prebuilt (compaq, dell, HP, etc) or is it a custom built computer? How many of the white connectors (aka 4 pin molex) are coming out of the power supply (total not just available) and what are they connected to? You may be able to get a splitter for it to and connect a couple of fans on the same one instead of buying a whole new power supply as long as that one can handle running everything.
That card under load uses about 330w though so it may be better to get a better power supply anyways depending on the rest of stuff running off of it. It would be a shame to fry anything in your computer because of skimping on the power supply. Honestly though it really depends on what your computer specs actually are and the actual specs of your power supply.