Thanks all for your replies.
I decided to spend a bit more money on this upgrade. With Bill Me Later option on newegg.com I could spend $500 bucks and get it paid off in 6 months with no problem.
So what kind of game settings will I get with these build?
I5 4430 3.0 MHz CPU
Radeon HD 7870 2GB GZH edition
Gigabyte B85 HD3 motherboard
Windows 7
G. Skill Ripjaws 8GB RAM DDR3 1600mhz ( I can always upgrade it to 16GB)
Also, don't forget that when you get new CPU you need a new mobo. When you get new mobo you need new Windows. So it's impossible to just simply upgrade your CPU. You need to build a new rig pretty much from the bottom and up.
You don't need a new copy of windows if you switch mobos. If you have problems activating it, just call Microsoft and they will help you.
Of course waiting until you can get the best system possible would be optimal, but with the amount of money you currently have available I would suggest something like this.
I5 3570k
a decent Asus mobo(P8Z77-V series for example)
8gb of 1600mhz Ram
7870 or the best you can afford.
I would not go for an A8 or an FX-6300 over an I5 3570k as the I5 will last you for years and it overclocks decently. Ive gotten mine to a stable 4.3. If you skimp on the cpu now you'll just need to reinvest in another cpu, mobo and probably the next ram standard. So down the road if you want another gpu just sell yours then upgrade.
Just my 2 cents though