upgrade desktop

Hey my current pc is an i7 4790 @ 3,6 , r9 290 sapphire toxic , asus hero viii z170 mobo , 8 gb dd3 @1600mhz. I have games like witcher 3 , fallout 4 with hd pack and mass effect andromeda among others , than i own but didnt played because i get very low fps in ultra and mediocre fps in...

I currently have an nvidia geforce gtx 560 in my tower. However I'm thinking of upgrading it. Any suggestions on a good one that isn't over 300 bucks. Also If i decide not to upgrade then I'll spend a little more on the laptop I am going to buy for business (hoping to kill two birds with one...