Is to go ahead and shop the HDTV and look for UHD with the new HDR feature then use what you have now. For example many have the BluRay with 1080p so just us that and let the UHD upscale it for you. Then in a year, go looking again.

Besides that chart you may have seen shows you may have to sit at 7 or less feet to the screen to see it.
http://s3.carltonbale.com/resolution_chart.png