Hi guys I am a bit new to building a computer

I am saving some money to build a new pc

I need to buy/upgrade some parts for my pc and the one I have are not bad can run bf3 but not on high settings and wish to upgrade to run some awsome graphics I need some help on the following Hardware

Graphic card
Mother board
Sound card
Case (optional)
Power supply (I have 1 of 880W but if I can't use it I will get a new one)

Any help would be appriciated if someone knows a website with cheap prices compared to others.

Price 800-1000 Euros

Thank you