I would cut it back and bring it in, force dormancy.
I wasnt even aware my area was getting a hard frost last night, thankfully my mother called and told me. had to cut them back in the dark and bring them in.
Good luck, I hope she makes it!

I have 3 and they are quite large...not sure how I'm going to get it done easily...but I guess I can just cut back at the base leave a few inches? is that what you did?

I have mine in pots, but they were climbing up a fence, I just cut them right where they were starting to climb on the fence, maybe about 2 to 2.5 feet up from the base of the plants.
When they started climbing ealy in the year I made sure they went up a bit before I started letting them climb, just for this reason..I didnt wanna have to cut them down too far.
I read somewhere, probably on here, that you should cut it down to 2-3 ft before forcing dormancy. So if i were you I'd try to do that..maybe if it's not grabbing onto too tightly to whatever it's climbing up you can sort of unwrap it so you at least get the 2 ft.

Well I just went out in the dark (like you did) and cut them back...and put them into a shed out back...it's sealed up so they wont get the cold like outside....It's probably as warm/protected as my garage is.

I tried to save as much of the vines as I could...because I could not really tell if they were all damaged...I really do hope to have my GH done in a few weeks or less...and tomorrow is the last day for awhile that will fall in the 30's...the rest of the week on is mid 40's and 70's in the daytime....

They are supposed to stay at temps between 50 and 60 while in dormancy, if I'm not mistaken. But alot of people have overwintered theirs in their unheated garages/sheds with good luck. Just pop it back out when weather warms up and she gets right goin again. I have mine in my enclosed, unheated, back porch along with my bananas and some other things.
I brought alot into the house this year to try and keep them going thru the winter..we'll see how I do..I'm a bit a-feared, lol. And now also maybe regretting it a lil bit since about 20 mins ago a lil rolly-polly pill bug fell out of a pot on the shelf over me and bounced off my head onto the k-brd.
Anyway..I think yours and mine will be fine as long as no more frost gets them. Greenhouse?!? I am SO jealous! I want one so bad. I'd love to have one attached right to the house..I think I'd spend most of my time there, lol.

After a few days and closer inspection...I am afraid the cold got them worse than I had initally thought...they are looking dead...so, any chance that the roots are still ok? and they will come back?

I don't know, but I wouldn't give up hope. I'd keep her thru winter and see if she pops back in spring. I can't tell you how many plants I bought at Lowes and HD on the reduced rack, and the employess told me, it's dead, theres no way you can help it..yet I have had about a 90% success rate at having them live, and thrive beautifully.
The branches and leaves are so much more exposed than the roots, so I think theres a chance it would be OK.
Good luck!
Daniella