It will work on the motherboard no problem. But it will SEVERELY bottleneck with your CPU. And as you want to upgrade to a Discrete GPU I am assuming you want to be able to at least run any game, new or old, on your PC.
In that case you might want to look for second hand deals for at east an i7 920 to replace your i3 if you are really tight on cash. You should do this before adding the GTX 960.
But I would honestly recommend saving up a bit and AT LEAST upgrading to:
Intel i3 8100 with a budget Z370 board or with a B360 board when those are available.
Or
Ryzen 5 1400 with a Decent B350 board like the Asus Strix or the MSI Tomahawk.
8 GB RAM ( 1 Stick of RAM so that you can upgrade it to 16 with another Stick later on as prices are...