it depends on what you're planning to get out of the pc.
if the current cpu is bottlenecking whatever it is that you are doing, then go for a skylake.
if that's not the case, then go for a better cooler and a new case.
although the h100gtx is a good cooler, the hyper 212 evo would be a more budget friendly option.
But i have overheating issues at times, and i might look into overclocking.