Ok i have a
cpu: 2500k at stock speed right now
Video card: HD 6950 2gb at stock speed
8GB DDR3 ram
win7 64 bit

I think this is a very good setup but im not getting good performance after the high res pack + DX11 at 1080p resoulution

Any advice????? overclock the cpu maybe?

PS: I overclocked the GPU and it didnt help , do you think i should get another video card and run two 2GB cards or get a good i7 cPU ??

please define what you consider to be poor performance. With out some facts to go along with your question it will be impossible to do anything for you. If its because your FPS dropped considerably I would be quite suspect of AMD's drivers - start pestering them to release some that work like they should. I have a GTX580 and while I took a FPS hit im still never going below 30 with everything maxed out. Most of the time I'm moving along in the 60's. You also have to keep in mind that with the highres pack and the extra geometry from tessellation you are looking at 2x-4x the number of calculations per frame that have to happen - so your going to take a hit no matter wha