Your 8gb RAM is fine for now.
Your GPU performance is somewhere in between the 1050ti and 1060-3gb.
Your CPU is 4 generations old i5.
Considering all of that, the CPU should be your first priority before anything else. A 4790K can get you close to 8400 performance...
http://cpu.userbenchmark.com/Compare/Intel-Core-i7-4770K-vs-Intel-Core-i5-8400/1537vs3939
A 1070 along with it should compliment well. If you want cheaper then, looking at 970/980 would be good idea. A 980ti can get you 1070 performance if you can find it cheap... http://gpu.userbenchmark.com/Compare/Nvidia-GTX-980-Ti-vs-Nvidia-GTX-1070/3439vs3609