The requirement is 42 amps on the +12v rails:http://www.evga.com/products/moreInfo.asp?pn=015-P3-1583-AR&family=GeForce
500 Series Family&sw=
Most quality 600w psu's will fill the requirement.
A quality psu will come from Antec, Seasonic, XFX, PC P&C, and Corsair to name a few.
Here in the US, XFX has well priced units, like this 650W unit:http://www.newegg.com/Product/Product.aspx?Item=N82E16817207002
It is modular too with 52A.