Cold is not your enemy: it helps...but you must keep the tank above 61.1 degrees. THat lessens the oxygen demand and puts fish and corals somewhat to sleep...
What you need most is aeration. A battery powered bubbler (Plax brand: your local Petco) is key. Plus a supply of batteries. But if you can't get one, get up on a chair with a pitcher, dip water and pour it steadily until the amount of your pouring has equalled tank volume. Then you can rest for four hours. Ace Hardware sells a hunter's propane stove with little bottles of propane that are safe for heating indoors IF you crack a window---otherwise it can kill you. Got it? I did that for 8 days and pulled several of my fish through plus the tank, plus all the corals. Inverts, only snails and crabs lived.