Great, so the RX 500 series cards come out tomorrow. The general consensus is that they will only be marginally better than the current RX 400 series and with a higher price tag. If you want to go with a more powerful card; you can check my further recommendations below.
These two cards sit around your current processor's performance range and are bang for your buck:
AMD RX 460 $89.99
This is currently ranked as the best price/performance card at this time. Performance ranked at
4288
Nvidia GTX 1050 TI $129.99
Ranked the 4th best price/performance card at this time. Performance ranked at
5801
If you would like to pick up a card that will last you into your next processor; I suggest :
Nvidia GTX 1060 3GB $179.99
Don't mind its small size, it is still a 1060, and ranked the 3rd best price/performance card at this time. Performance ranked at
8559