Upgrade your PSU first but you will be unlikely to get a GeForce GTX 970 in that price now unless you get it used (which isn't a problem if there is a reliable seller). But if you want to get a new card, wait for NVIDIA Pascal to come out.
For the PSU, I would suggest a good EVGA 650W because that is more than enough and will be fine for the future.
Unfortunately I can't link you to a good one right now because I'm writing this on an iPad and I'm away from my computer and copying and pasting is annoying as hell.
Hope this helped.