I have a similar setup to yours, using a i7 3770k, and I recently went fishing for a good deal on a GPU. Found a RTX 2070 for $450 with no tax/shipping, and it should be arriving in a few days. I am hoping this one upgrade will help out the most, because it was my main bottleneck, especially with the direct x 12 changes offloading cpu power needed to the GPU instead.

If you plan on upgrading the entire system anyways, I'd test out just doing a good video card and then go from there, that may be all you need.