Help needed! - can't decide what to do, need proper advice?

Although it might seem like I already know the answer to my problem, I'd still like to get some advice.

The problem:

I've got $1, 200 and I'm trying to decide whether to buy a camera (Nikon D7000/7100) or upgrade my PC. Which if I were to do so, it'd be a total of $1700 for the PC (I already invested in a graphic card - $412).

Photography for me is a hobby as of right now; I'm studying Graphic Design and I do like the creativity involved with photography, specially for Long Exposure, and night landscape which are my two favorite categories/techniques to do. As for the computer, I'd like to say I'm an above average gamer, I use my current computer almost every single day for 2 things only, browse the internet and gaming.

Now, I already have a camera (Nikon D5000) and a gaming PC (quad/8gb ram/GTX 770, etc.) but I'd like to upgrade to something a little better.

Bad thing about the camera is that it's family borrowed, so I just have it for an indefinite amount of time until the person who owns it wants it back, so technically I do not own a camera of my own.

Feel free to advice me in anyway possible, will listen to anything and everything, thank you so much in advance!

Reading between the lines, the gaming seems more important to your current lifestyle than the 2009 camera which you have on loan and which works perfectly well. Given that Graphic Design demands an up to date computer capability, presumably with Photoshop from the Cloud now and other software, then the PC upgrade should be what your head tells you to do especially as you already have a new graphics card.
Next year a D7100 will be what a D7000 costs now.