Any chance you'll make one in the next month or so? If so you'd be fine to just refrigerate the swollen pack.
For the bucket temp, you could move it near a water heater, get it off direct contact with the floor if that's a problem, wrap it up in some towels for insulation or just move it to a warmer part of the house. The 18 hours is not an unusually long lag time, but the low temperature may well be contributing.
Another though on using the second pack, did you make a starter for the first one or just add it directly? You may want to drop the second one in there after all if no starter was made. What was your starting gravity?
Edit: NB says the gravity should have been 1.040. One pack should be enough, just get it warmer. If you won't use the other pack in the next couple months just go ahead and toss it in.