Upgrading to 16GB of RAM, or better yet, finding an 8 thread i7 Haswell/Refresh CPU, would probably be the MUCH better upgrades if you desire to stay on the platform you have for now.
An i7-4770, 4770k, 4790 or 4790k would likely offer far more in terms of a performance increase than anything you could do with the memory INCLUDING increasing the capacity, although that couldn't hurt either, but is probably not worth buying an entirely new set for since that is what you'd have to do in light of having only two DIMM slots.
I don't agree that waiting until next year is advisable if you NEED an upgrade now. Maybe waiting until the new Ryzen SKUs are released in July, but not necessarily until next year. There is always something better on the horizon and if we always waited for it we'd never do anything, frozen with indecision. There are options, places to go from where you are now, that offer real benefits in terms of performance advantages, now.