Upgrading my GPU

[Phoenix]

I'm looking for some help with GPU upgrades for my i5 4690k. All I want is for the game to run smoothly. Currently, I'm using 1440p on a 27-inch 60-Hz monitor, and I'm able to maintain a reasonably constant 60 frames per second at low settings.

My specifications are listed below.

CPU: Intel Core i5 4690k

MSI Z97 Gaming 5 MOBO

16 GB CL10 1866MHz RAM