Build Help

In short, i'm trying to decide whether i should add a second GTX 650ti Boost from EVGA or should i go and get a better single card gpu from AMD? My budget isn't really set, need to save up a little more money before i can do anything but want to make a decision before i can do anything.

Current set up:

Mobo: Asus M5A99X EVO R2.0 (Socket 942)

Cpu: AMD FX-8350

Cooler: Cooler master hyper 212 evo

Ram: Kingston Genesis 8gb 1600mHz

Gpu: EVGA Geforce GTX 650ti Boost

Psu: Antec 600w

Case: Antec six hundred v2

I'd suggest a new single GPU:

http://www.newegg.ca/Product/Product.aspx?Item=N82E16814125439&AID=10657534&PID=3938566&SID=&nm_mc=AFC-C8junctionCA

:)