If your current GPU is a 5450 you dont need much in terms of power.
A GTX 950 has the following:
HDMI 2.0 (make sure your monitor is HDMI 2.0 capable)
DisplayPort 1.2 (Also 4k capable)
https://www.geforce.com/hardware/desktop-gpus/geforce-gtx-950/specifications.
A GT 1030 would be a cheaper option and has DisplayPort 1.4, and HDMI 2.0b
https://www.geforce.com/hardware/desktop-gpus/geforce-gt-1030/specifications
The GDDR5 version is faster but either of those is a big step up from a 5450
If your applications can benefit from CUDA acceleration that stepping up to a 1050 will yield a big performance increase in productivity.