7870 need 160W w/o OC.
So better find a 550/650 W Psu so u can CF later than that Cx 430 V2.
I suggest Xfx 650 W Pro Core or Tx 650 V2 that is on sale on newegg.http://www.newegg.com/Product/Product.aspx?Item=N82E16817139020&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-na-_-na-_-na&AID=10446076&PID=3938566&SID=
The Xfx 650W is made by seasonic.
Also the Tx 650 V2 is made by seasonic so you cant go wrong.
77W Cpu W/o OC
160W Gpu W/o OC
=300 W lets say you want to CF =560W W/o OC. Add 40 W and here we come to 600 W.http://www.hardwaresecrets.com/article/XFX-PRO-650-W-Core-Edition-Power-Supply-Review/1165
The Xfx 650W deliverd 720W on the 12V rail so its way enough.
Good Luck !
Edit : If you already have those 2 PSU use the Cx 430 V2.It will power your system way better than that crappy TR2.