RAM is one of those things which isn't a problem until you run out of it. At least that's the way I see it.
I think winks42 is correct in their assessment of potential CPUs to upgrade to (and the relevant motherboard to support it). They're the ones to look at for actual performance gains over what you have.
The leaks of the next Ryzens suggest something really impressive, but we'd need the benchmarks to confirm it. I believe we're looking at May for any solid information. At the very least, if it's as impressive as leaks suggest it may force Intel to change pricing strategy.
I would also suggest checking out whether anyone has run benchmarks for the software you use (or intend to use). Reason being that some software are still rather limited in taking advantage of the number of cores and threads the newer CPUs offer. If the software scales well, then Ryzen should be a very strong contender for consideration. If it doesn't, then the likelihood is it is reliant more on IPC which tends to be Intel's advantage (whether the Ryzen 3000 series will change that we'll have to wait and see).
Supposedly RAM prices should drop this year. And it does seem a waste to purchase DDR3 now for possibly negligible performance gains.
Best to save up for the new platform overall, I think, to ensure the sort of performance you need when you make the switch and use for a few years to come.