Upgrade CPU first (including MB and RAM) to allow your rig to upgrade to more powerful GPUs (such as the GTX 1060 and above) in the future.
Consider going for an AMD Ryzen 5 1600 CPU + B350 Motherboard + 16GB (2 x 8GB) DDR4-3200 RAM, if your budget permits.
If budget is too tight, consider going for an Intel Pentium G4560 + B250 Motherboard + 16GB (2 x 8GB) DDR4-2400 RAM (which can handle a GTX 1060, much more your current GTX 960), and upgrade the CPU to an i5 or i7 much later on.