Douglas Doman spoke about the heated floors for this climate. Then you just have to rebuild your house
My child was also born in February and the winter was very cold. Minus 20 C and lower, for the long time. The floor was cold despite of heating. Every time I put my child on floor (on four layers of carpet) he got cough. So he lived in a bed. If the bed is not very soft he can do the tummy actions rather successfully. Maybe you can put some board in bed; in the first months, your child will not move anyway.
Digg
