Your refrigerator should operate okay down to about the 20s but if those temps remain in place or go lower long term you should close off a couple of the vents behind the unit, put in a 60W bulb, disconnect and drain your water line and icemaker valve then just buy ice.
Our icemaker valve froze at 29 and with pressure to the line it ran water down the driveway and flooded the inside too. Those durn valves are plastic so if they freeze they are broken.
We fought it for a while then decided, especially since we don't like tank water ending up making ice now and then we just unhooked the water line and buy ice. Commercial ice tastes a lot better than ice from "where ever" you have been and sure saves a lot of hassle.
Friends of our gave up on the icemaker situation too and bought a table top unit they can fill with bottled water. But those take up a lot of room but it is a fulltime option.
