1) If you aren't using an SSD get a faster hard drive, 5900RPM is slow.
Check out the Western Digital Caviar Black series.
2) For "high-end gaming" you certainly want a better graphics card.
To put it in perspective that card is #197 on the GPU performance list
3) I may be wrong, but I doubt you'll fully utilize a 6 core CPU.
PII x4 955 BE
is $120 and better for your needs.
I would suggest posting your budget and letting the community offer you up some better options.
Please read through the thread thoroughly before responding.
Nobody wants to read a wall of text, formatting is your friend.
i5 3570k | 8GB G.Skill 1600MHz | R9 290 | SeaSonic 750X