I guess it's a good thing my PS3 got the YLOD, but I really want to play this when I get a new one. Should I wait on the patch that they're supposedly working on, or take it back?

Take it back, if they "are" going to fix it, it probably won't be within like 2 weeks. Just wait for some feedback. Trust me and save your money.

There's nothing stopping you from taking it back even if you have opened it, if for some reason the store won't refund your money threaten them with trading standards. The game is faulty and therefore you're entitled to a refund, you had paid for a game having faith in a major company it isn't your job to guess whether it is working correctly or not before purchase that is down to the company that made said product.

SELL SELL SELL SELL SELL SELL


If you can return it and get your money back, do it. Like don't even think about it, go, NOW!

hate to say it but take it back until you are sure there gonna fix the save and framerate issues