Dog Father
Recon 3 Sleeping Bag
Bic Lighter
iPod loaded with some new audiobooks.

I would spend the first half a day building a shelter with the materials you preloaded in my pack, getting water if the bottle you put in is empty, getting some firewood and picking up any shrooms or other edibles along the way. If I don't find any food, no big deal, its only 48 hours. Hell, the shelter is mostly for comfort anyway for that time period at those temps. I could always just make a bivy out of the tarp and put the sleeping bag in it. I could go two days in those temps with out water as well.

Once the above stuff is done, I'd make a fire in my shelter, bundle up in my bag and listen to some good stories while I wait out the weather for the next 36 hours.