>>300136631
You'll have to upgrade your PC either way. A 2013 card and presumably also old CPU isn't going to run even the lowest spec VR game.
So, the actual choice is between VR, a 1440p 144Hz monitor, or a 4k monitor.

If the low selection of VR games is already very exciting to you, get VR. 
If you are playing a lot of videogames, get the 1440p 144Hz monitor. 
Only get the 4k if you basically only watch movies, and even then 4k is a meme, AFAIK.