First, let me say how sorry I am to hear of this disaster.  So glad the birds are OK.  Losing your coops is a difficult situation, especially with new birds coming.  I think trying to get someone else to take them, at least temporarily, is a good idea.  
The home improvement stores are selling outdoor stuff cheaply right now.  You might also check the Habitat for Humanity store for used, cheap building materials.  They have a lot of good stuff.  Some folks would probably help you for free eggs for a while.
When I needed a second coop, I built a quick "temporary" coop inside a detached garage out of 2 x 4s and chicken wire, and it's the most popular with the chickens!
  
Heat lamps around hay and dry wood shavings scare me to death!  Chickens don't really need heat, even in northern climates.  They are hardy to at least 20 degrees, maybe colder if they have a draft free place to roost.  
Another option is one of those thermostatically-controlled oil-filled radiators.  No open flame and they don't get extremely hot, so if you built a little cage around it (prevent roosting) and kept the shavings away, it would warm a good area.  They are only about $35.
Hope you find what you need.  It's not fun to be out building in miserable weather.  Maybe you'll have some clear, sunny days to get done what you need to do.