Have you factored in what you can get for your GT 1030 in your budget? After fees you should get about $60 for it. At around $160 you could get a used GTX 1060 or 970.
At $100 you can get a GTX 960 2GB used or possibly a GTX 960 4GB.
Your case and PSU also matter. Without knowing those. I could not say your PC can handle the beefier cards.
As mentioned the GPU hierarchy is also good. You can look for other cards on eBay in the GTX 960/970 performance brackets.