Holy crap! Where do you live, in Canada? I may have broken pipes even though they were wrapped. I'm not getting water to the greenhouse yet.
Where's Al Gore when you need him.
I am so sorry, that just sucks. BUT, I doubt if 30F is gonna do too much damage if it was for just a short period of time. I'd give it a few days before really doing some heavy duty pruning.
I know hindsight is 20/20 but you might invest in more heat. I like the top mounted cone type heaters for 25 lb. propane tanks. You can get them with 1,2, or 3 cones. If you need more get this one from HD. I have it as a backup for my greenhouse as my big boy relies on electricity to run and you never know when the grid may get loaded up and go down. It really kicks butt and cheap. Heck, the regulator and hose alone would be about $35.
http://www.homedepot.com/p/Dyna-Glo-50K-80K-LP-Convection-Heater-RMC-LPC80DG/202895381?N=c6zn#
Another option - reveg for about a month, flower again.
Good luck!