Technically it depends on your other computer specifications, but I can assure you that your power supply is sufficient for that graphics card, the minimum recommended wattage for that GPU would be 500 W and that's for a crappy PSU. If you want to be absolutely sure go to http://outervision.com/power-supply-calculator and fill in your PC specs, it will calculate the wattage you will need to keep your PC running.
Also your card will use up to 150W maximum if that helps.