You could move up to an i7 3xxx series CPU. It's likely that what's holding you back with that i5 is the lack of more than 4 cores/4 threads. I'd be willing to bet that in those games, once you have 8 threads then your performance will be based on the videocard and not on the CPU.
Of course the new Ryzen and Intel CPUs would remove any CPU concerns, but right now is really the wrong time to build one of those computers if you can avoid it. The other potential issue is the cost of an i7 3xxx series, depending where you live it might not be worth it. You'd sell your i5 too, to try to mitigate costs.