That's definitely too cold. The minimum recommended temperature is 73*F, about 22.7*C. Can you change the house temperature & keep her in the warmest room of the house until you can get a heating set up? It sounds like you need one ASAP since you can't depend on the house heating and she's already had one hibernation attempt.
~*~*~ Kelsey ~*~*~
RIP my sweet Lily ~ 6/12/08 - 1/20/12