No matter what my budget is, I always try to spend good money on my PSU. I've had a whole system become useless because of one bad PSU. My recommendation is save some money and buy a nice semi-modular one.
Nvidia's naming sequence can sometimes throw people off but I'm glad it worked in the end for you. More than a 50% increase in performance. That should keep her happy for a while.
Get a used 290x for 300.
Edit: Nvm, just realized that gtx 970 runs as well as a 290x. In that case, I agree with everyone and say you should get a new gtx 970 or buy another 270x for CF if you're on a budget.