Upgarde my cumputer

Hi

  I currently have:

MSI P67A-GD65 B3 

Intel Core i5-2500K /3.3GHz, 6MB, LGA 1155, BOX

Gainward GeForce GTS 250 512MB DDR3/256b PCI-E DG 

2 x Kingston HyperX DDR3 2 X 2GB 1333MHz CL9 (8 GB) 

Samsung 1TB 5400rpm 32MB cache SATA-II F2EG

Corsair 600W CMPSU-600CXEU 

Windows 7 Ultimate x64 

  What I will want to change:

1) I want to buy ASUS GeForce GTX660 2GB DirectCu II OC and sell currently one (GTS 250).

2) I want to buy new disc Seagate Barracuda 7200.14.

3) I want to buy cooler - maybe this one - Noctua NH-D14.

4) I want to overlocking my CPU - maybe 4,2 or 4,5 GHz? We will see.

  And finally my questions. Could you tell me if is it any chance do this? Do you know if my power supply - 600 W will be enoght for overlocking? Is it any chance for 25-30 fps using 737 NGX, Aerosoft Schipchol, REX, GEX, UX after overlocking? Maybe other alternations?

  Thanks a lot for helping.