Id get a 7870 for a GPU.
Performs much better.
Usually gaming builds have 8GBs of RAM, depending on what you play, you may or may not need 8GBs. SSD could be better. Id get a Vertex 4 inplace if the Force 3.
7870: Rs 22k
7750: Rs 6.5k
...There's a big difference....
Also, that Vertex 4 is costlier too.