Your motherboard supports: 2 x DIMM, Max. 8GB, DDR3 1066/800 MHz Non-ECC, Un-buffered Memory
Dual Channel Memory Architecture
You could get something like this:
http://www.amazon.co.uk/dp/B004CRSM4I/?tag=pcp0f-21 (Corsair CMZ8GX3M2A1600C9 Vengeance 8GB (2x4GB) DDR3 1600 Mhz CL9)
While this is faster than your motherboard supports, it will just reduce to 1066MHz. You can get 1066MHz RAM but the 1600MHz is cheaper at the moment as far as I could see.