here is the rest hardware:
CPU : i5 2500 3.3 GHZ
HDD: Western Digital Caviar Black 1TB
I found that PSU : http://www.corsair.com/enthusiast-series-modular-tx650m-80-plus-bronze-certified-650-watt-high-performance-modular-power-supply.html
Is this good enough?
YES. The HD7970 (non-overclocked) needs 40Amps. This PSU has 54Amps.
IMO, the best card available is the HD7950 OC from Saphire Tech:http://www.legitreviews.com/article/1862/
It has a GREAT cooling solution, can be overclocked, has a dual BIOS and costs about $490 at NCIX (USA). It was UNOFICIALLY overclocked by 45% though I would not do that myself. I would overclock to 20% above stock. Keep in mind you need MORE AMPS to overclock and it's not proportional. A 25% overclock needs close to 40% more Amps so keep that in mind.
You can use the above PSU and HD7950 OC and still have a modest overclock on the graphics card. Run FURMARK to test the graphics card for stability.