Better GPU for my PC needed - which one

[Rappa_]

So I have around 200+ € laying around after Christmas and I want to upgrade my PC.
Currently I run these parts:

AMD FX-4100
nVidia GT440
Corsair Vengeance 8GB
Asus M5A87

Which card won't bottleneck with my cpu and is a great performance improvement? Sadly, I can't get a GTX960 as it will bottleneck and building a completely new PC isn't an option for me.

Thanks and Cheers

 

[rolli59]

GTX750Ti or GTX950