A good rule of thumb is your graphics cards new price should be a at least a little higher than your cpu to make the most of your processor . Many games will not max out your cpu so dont be afraid you are wasting money on your graphics card if you spend a bit more.
For example; If I bought a £90 i3 cpu I would want to spend at least 120 on something like a gtx650 ti to get the most from it. Putting in a gt440 would
limit the gaming experience.