It might be, but I wouldn't trust that offbrand psu to run anything. A corsair 430W would be good.
What about for the HD7770? Also, i'm not sure if the 7770 would fit because its dual slot sized. I looked in my PC and it looks like there is room above my PCI-E slot. It has 1 PCI x16 and 3 PCI x1's above it.