That PC comes with a 350w powersupply, that WILL NOT POWER that card. You NEED at least a 500w to 750w power supply.
Anytime you buy a computer from bestbuy, office depot, etc and you want to upgrade the graphics card, you almost always have to change the powersupply.
My recommendation is probably a 600-650watt powersupply. Its right in the middle so price shouldnt be too bad.