Any recommended system upgrades?

[Olivr_Ep1c]

I'm getting pretty average fps while playing ARK: Survival Evolved, and want to upgrade my system so I can play it with less lag, and play more resource-intensive games. This is my system at the moment:

CPU: intel i3-6100 @ 3.7GHz 2 physical cores 4 logical (hyper threading)
GPU: Gigabyte NVIDIA GeForce GTX 950 OC 2GB
Memory: 16GB Corsair Vengeance LPX @ 2666MHz

What should I upgrade? Thanks.

EDIT:
My budget would be around $300 AUD
I would prefer an NVIDIA GPU, as I am running arch linux. NVIDIA cards are more optimised, and have better driver support for linux. (generally)

 

[Chugalug_]

Upgrade to an RX 480 or 1060 followed by an i5 6500.
Budget?

 

[Martell1977]

Whats your budget? Upgrading the GPU would be the first thing to do, CPU next. This is assuming your PSU is of decent quality.