The wattage recommendations provided by the Card manufacturer is a expanded calculation of the wattage being used by all of the components in your system. All working at full load. But it is always recommended to go with a higher Wattage PSU for safety and proper working of the system. I would recommend a PSU with at least 750 Watts to support any future upgrades as well. But 650 Watts PSU will also be enough. The only thing is, it should be of good quality. In this case, even a very good quality 550Watts PSU can also deliver results.
Your PSU has if I am not mistaken, has max 45Amps capacity on the +12 valt single rail. That sums up to 540 Watts of power on 12 Valt rail. This is the rail that is used to power the CPU and also GPU. I think this PSU would be okay.