What should I upgrade on my rig to fix my FPS.

Posted a DxDiag, but my question is what exactly am I supposed to upgrade on my rig?
My problem is that I'm getting low fps in some games on mid-high settings. GW2 15 FPS lowest settings in WvW when I'm looking at 50+ players, LoL at 10 FPS with everything on high.
I'm not really computer savvy and I don't know anyone around so I've came here for help any ideas on what I should be upgrading and what I shouldn't would be much appreciated Thanks everyone!

EDIT: Put DxDiag on Pastebin since it was taking up too much space on the screen.
http://pastebin.com/wth5JVdf