Upgrading your CPU would mean building a new PC - new motherboard, new CPU and highly likely new RAM. The only other CPU for your PC is the x4 880k which is not a worthwhile upgrade.
According to Tom's hierarchy chart a GTX 1050 would be a decent upgrade, as would an RX 460. Will depend on what sort of games you play and the budget you have available.
Upgrading your CPU would mean building a new PC - new motherboard, new CPU and highly likely new RAM. The only other CPU for your PC is the x4 880k which is not a worthwhile upgrade.
According to Tom's hierarchy chart a GTX 1050 would be a decent upgrade, as would an RX 460. Will depend on what sort of games you play and the budget you have available.
I am right now using an r7 360 and an x4 860k and wondered what one I should upgrade first
Yep, upgrade the GPU, because it is cheaper and easier, then upgrade the CPU. You could get an Rx 560 or Gtx 1050, however anything below that is terrible value.