Before you do, make sure you have the needed PCI-E power connectors for the new card available, then shut down, unplug, remove the old card and install the new one, plug in it's power, plug in the rig and start it up - go to the GPUs site and download the latest Drivers (if newer than what you already have) and tuning software for your new GPU and your ready to go
And is this a good card to buy http://www.amazon.com/EVGA-GeForce-GTX650Ti-Dual-Link-Graphics/dp/B00BZB0HDS/ref=sr_1_10?ie=UTF8&qid=1383250031&sr=8-10&keywords=gtx+660. Also I dont know if I have enough power supply for a card this size. If I do need a new power supply some suggestions would be appreciated.
Would this one be okhttp://www.amazon.com/Corsair-Builder-Series-Watt-CX500/dp/B0092ML0MY/ref=sr_1_2?ie=UTF8&qid=1383543506&sr=8-2&keywords=500watt+power+supply If you have any links for units you would suggest that would be helpful also.