There is NO EXACT bottleneck point.
Some games use much more GPU, and some use much more CPU on average. It also depends on resolution and other game settings.
We can speak on AVERAGE though and say that a much better GPU will give you much better performance on average and that there is no card (even a GTX1080Ti) that won't be bottlenecked by a Ryzen CPU. On average.
There are conversely games that will still be bottleneck on your CPU though they are going to be much more rare (though again, at lower resolutions, less anti-aliasing etc the CPU is more important).
The GTX1060 6GB is probably the best choice right now.
What you mainly want to know is how BETTER you can do with this card?
https://www.techpowerup.com/reviews/ASUS/RX_460_STRIX_OC/24.html
Your numbers would be slightly lower compared to the Intel at 1920x1080 and less so at 2560x1440. If we use 2560x1440 then we see on average 2.33x the FPS.
Let's call that 2.2x on average so up to 2.5x+ in some games when optimized more towards NVidia, and less so in other games since this is an average of about 20 games.
(or more realistically a combination of FPS and higher QUALITY settings)
I'll post this and find prices, though you may want to consider holding off for the GTX1070 which is guessed to drop to about $350USD in a few months (once crypto-mining disappears, and with the possible introduction of a GTX1070Ti).