help for upgrading pc ?

Solution
Stick with a 960 or 950 and you don't need to. Either would do a decent job of what you ask the 960 would firmly max out your cpu

Supahos

Expert
Ambassador
You don't mention memory but assuming you have 8gb your best bet is to add a gtx960 or 950 if that's all you can afford. I wouldn't put an amd video card in it since you have a small power supply the 960 and 950 should both be fine with current power supply
 

game junky

Distinguished
I would upgrade the power supply and install a graphics card - I would ask yourself what your expectations are in terms of performance and how much you're willing to spend first to steer your choices.

Graphics card should be your starting point - if you're playing on a single screen at 1080p and want high settings across the board with the exception of some of the most demanding games, you're looking at an Nvidia 960 or an AMD R9 380X as good options under $250. You can step up to the 970 or 390 for higher performance but there is a significant step-up in price for both. Your processor will become the bottleneck making that change and you'll want to make sure you have 8GB of system memory because some games will take up to 4GB or more of RAM in large multiplayer maps. Might also be worth considering adding a nice CPU cooler and overclocking that processor to increase performance