Ok first : If you like to play triple A games an upgrade to 16gb system memory and an i7 7700 would be a night and day difference for high refresh rate gaming. However for esports titles like csgo, league of legends, world of tanks and non demanding games at 1080p I would just go with the system memory upgrade.
Second: If that AOC Monitor is only 60hz then that means you only need to push your hardware to hit between 60-80 frames per second to get optimal performance. If that's the case, just upgrade the system memory and see if you hit that fps target with the games you play.