No, yeast are fine at that temperature. Your mash volume is more likely to be the issue than a downspike in temperature.
If you taste it, and it tastes sweet, then you have a stuck fermentation. If it doesn't taste sweet, then it's fine and will be ready to bottle soon. Just take another hydrometer reading, and if it's the same as the one above then the beer is done fermenting (it might still be cleaning up it's side products, though).
If you don't want the gravity that high, you have a few options. Get some enzyme from your LHBS (you can use Bean-O if you want to). Or add some champagne yeast in there and see what they can do. Basically, until you have taken another hydrometer reading and tasted the beer to see if it tastes sweet, then you don't have enough information to proceed.
If you want a low-risk "something" to do right now, try swirling the closed fermenter to get some more yeast in suspension. It might help. It won't hurt (unless you spill).
That's just my opinion.