I'm not sure what you price range is so i'll give a few suggestions both amd & nvidia lowest to highest:
On the low end i would suggest an amd rx560 or a nvidia 1050ti. they'll both be better than what you have and will give you some better performance while saving the most money, just make sure you get one with a good amount of memory. Note with these cards the performance boost might not be what you're looking for so watch benchmarks.
Some avg. fps #'s for these two
(not overclocked)
gta V ~ 43-46
csgo ~ 111-120
If you're looking for the next tier up I would grab an amd rx580 over the 1060. This is going to get you the most bang for your buck. It's right on par with a gtx1060 while being able to find it for significantly less expensive. You'll be able to see the performance increase right away. Again with this one try to find one with the most memory.
Some average fps #'s for the 580
(not overclocked)
csgo ~155
overwatch ~100
battlefield 1 ~73
pubg ~70
gta V ~ 60
I'll leave it at that for now since you said a 1070 is too much, if you want some more alternatives in this price range you can look at the gtx1060(the 580 is cheaper for about equal performance), or the rx570 (much better than 560, little worse than 580)