which order

Ok some may have seen I asked in another post inquiring about which gtx980ti to buy,but on reading some other posts on monitors I'm now wondering if a monitor upgrade should be on the cards 

I'm very restricted for room, so the best at the moment i can get is a single 24in monitor.

I've had a look around and I can get a dell 24in 4k monitor for a reasonable price, so should i buy a monitor or graphic card first?

Currently I'm running a dvi connected monitor in 1920-1080p with a gtx780ti  3gb card. I plan on basing my sim around p3d v3 so although at the moment my card is probably fine for my current setup 

I would really like to move the sliders more right,which i'm guessing will put a much bigger strain on the current card 

So what would be the best way to go ? monitor or card first?

I think my cpu is man enough i7 4930k and have the program and addons on an ssd so they probably don't need upgraded (just yet !)

Thanks