I would get a better graphics card first, are you planning on gaming at resolutions of 1080p or higher? A gtx 750ti would be a solid upgrade but you'll like the gtx760 better. I've used both cards (overclocked of course) to play most games at 1080p, played fallout 4 at high/max settings at 1080p ~60fps vsync on the gtx760 oc'd by 1ghz on the ram.
If you want to game at even higher res you'll need a better card like a 780 or a 970 or for 4k a 980 or 780ti.
Also I would buy an aftermarket cpu cooler and try for 4ghz if you're comfortable overclocking.