Sapphire 7950 Vapor-X
Intel Core i5 3450
ASUS P8B75-M LE
Corsair Vengeance 2x4 GB
NXZT Phantom 410
Its mainly for gaming, but i want to know if the motherboard and cpu are going to limit the ingame performance, because im out of money and i dont know if adding a i5 3570k and a gigabyte ga-z77x-3dh would worth the sacrifice?
No your cpu will not bottleneck your gpu. The i5 3450 is a pretty capable cpu. It is totaly NOT worth it to upgrade to a 3570k. Your gains will be minimal unless you plan on overclocking the 3570k a bunch. Lastly the motherboard doesn't really affect performance as long as the pci-e slot is running at 16x speeds (which i assume it is because only one slot is used).
I'm not sure about the motherboard but definetly spring for the i5 3570K (Seeing as how the price difference is quite minimal) those chips along with the 2000K can overclock incredibly well (4.0Ghz +) and worth the long term investment because you always have the option of increasing your performance with no future charge, except maybe a cooling solution if you plan to push past 4.0Ghz.
Your 7950 as well as a down the road crossfire with another 7950 will appreciate you did.