Just to be sure, when you say it barely runs the game, what exactly do you mean?
If it's just not running at high graphics, it's the GPU, it's 2 models below the recommended card for high graphics (950 not 970). I would recommend upgrading that if you want to upgrade anything. I would say something like the 1060 or 1070 would be a good choice.
Upgrading is very easy, almost as simple as unplug the old and plug in the new. If you need any help with choosing a new card and installing it just ask.