I would recommend to take a considertion about upgrading your proc without changing anything else.
G 1610 is 1155 proc correct? if I am not mistaken.
Try to look at i5 3220, i5 3570 or i5 3570 (non-K) and see which one you like and fit to your pocket. Those can ballance HD7850 very well.
Edit:
If you are tight on budget, i3 will also do the job