change the PSU to this: Seasonic X-650
but stick to the GE FORCE GTX 670 EVGA
AMD's OpenCL video cards are not supported in PremierePro under Windows, nVidia's CUDA sure are. You need at least 16GB RAM (Corsair, Kingston, Crucial, Geil, G.Skill). Also consider a beefier Cpu. i7 would be best suited for Premiere Pro and FL. SSD as a system/apps drive would be a great improvement too.