That GPU is a pile. Its a very low end gamer if that. 6950-2gb is the sweet spot. Any stock reference card will work. If you want to unlock it then you have to do legwork and track down the right model.
There are about 3 different PSU units out there you are going to need to look at. For watt per $ around the holiday you can always find an Antec 800 or a Corsair that will work. Always peg around 800 watts. You dont want to run your rails all out and you never get what you pay for so the electronics rule 1-1 of adding 30% supply capability is in affect.
Never plan on crossfire or sli for that socket. Its a budget part. You are going to be running one card at 16x or multiple cards at 8x8 pretty much. In reality in most of the builds you find online its a 10% performance hit. Plan ahead. If you are going to invest that kind of money in a gpu then get top end. A 6990 or something comparable. Take out all of the performance problems you get with xfire/sli and save money on cooling.
I was looking at the EVGA 02G-P3-1559-KR GeForce GTX 550 Ti (Fermi) 2GB 192-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card and Was wondering if it would be better to go with a cheaper Video card and a SSD or this EVGA card.
I also am switching the PS to a RAIDMAX HYBRID 2 RX-530SS 530W ATX12V V2.2/ EPS12V SLI Ready CrossFire Ready Modular LED Power Supply.