I just barely(as in sunday the 23rd) got a new 600w powersupply and a XFX Radeon HD 6750, I unfortunately only have 4GB, but I can have as high as 16GB, so I might expand in the future AND I just got my new computer on the 21st of September this year! So i am super excited! It runs WoW more then wonderfully, and am hoping it runs GW2 amazingly well!
4GB of RAM is fine, but up to date comps now are running 6+. If you'd like to upgrade it's really cheap.