I'd stick with what you have for now.
Only consider an i7 if you're regularly using software that needs or benefits from its 8 threads: rendering or video editing, otherwise, for gaming, there's not enough performance gain over the i5, you'll be better off adding a decent CPU cooler and overclocking the existing part.
Again, for gaming, the GTX970 is about as good as it gets for 1080 60Hz monitors, you could move up to the mighty GTX980Ti but it's better suited to either 1440 res or a fast Gsync display at 1080/1440. Switching to a GTX980 will be a help at 1080 if you're having issues with minimum frame rates in very demanding games but the cost is fairly significant, a little trimming of the settings will restore smoothness with...