you do realise the built in graphics of your amd a8 is probably better than the geforce 520 card you have installed, right? apart from that either the 650, 650ti or 7770 is a real leap ahead from what you have now.
Im also interested in getting the 650 TI (gigabyte one), I did some research into the gigabyte vs the HD 7770 and what you see in the first becnhmark is accurate. so I would go with the evga or gigabyte 650 TI.
My question is do graphics cards work similar to cpu where the power usage increases in a way exponetially as you use more of the card or is it more a straight line