When looking at graphics cards, generally look at the 2nd number in the model (nVidia), 1st is effectively the year of production and the 2nd is the actual model)
So for eg. a GTX 650 is not as good as a GTX 560
use something like http://www.anandtech.com/Bench/CPU/2 to compare the cards your looking at.
I wouldn't recommend the 650 you posted...even my (2 years older) 460 out-performs it.
If you are limited on budget an AMD card will be better value for money than nVidia, but can lack things like Physx (however BF(at least 3) doesn;t support Physx so check if the games you play support it...if not then go AMD for sure as your limited on budget.
Similar rules apply for AMD cards, 2nd and 3rd number are more important than 1st.