Is 7770 a good choice for me?

Inspired by the "Cheap-ass" gaming rig, i build a system with very basic components since i didnt wanted something very expensive, my parts are CPU: AMD A4 5300, MoBo: AsRock FM2A72M-DGS, Ram: 1 stick 4gb 1600 Corsair Vengance, PSU: Corsair CX430.  the problem is that now i want to put a discrete GPU in order to be able to play newer games, i did some research i find out that sadly my AMD APU can only do Hybrid crossfire with HD 6670 but the boost in performance won't be very significant, and the card that i think will really help my system is the HD7770, but this one is not able to crossFire with my APU, so my question is: should i stiil get the 7770 and just use the gpu alone or try the crossfire with the 6670? which will be my best option?. Any suggestion is very welcome, Thank you.

If you can afford the 7770, get that. The performance increase offered by the hybrid CF is not enough to make it faster than a single 7770.