SteL

I would say it's about time. But keep in mind that in about 4-9 months (big range lol) the next line of Nvidia GPUs are coming out, so don't spend a whole lot. The next gen will be aimed at above 1080p resolutions. A 980 ti will beast mode games right now, but probably not for long. I would get something like a 970 to hold you over till Pascal. As that's what I am doing. But I have a 750ti and I want to pass that down and have a 970 to pass down as well. 

eh. i'd save up until the next generation of cards (on both amd and nvidia side)
and *maybe* along with it upgrade that power supply to something better.

I mean, that card is still good, it should not be replaced because of age. 
 
Saying that, it was never a powerhouse. 
 
Upgrading to a GTX 970 or a R9 390 would be reasonable.

well you can pick up a used 970 for really cheap, so that would be a good deal
 
or wait for pascal imo
then if you can afford one of the new cards, great
if you cant, plenty of people will be selling their old cards for even cheaper