Get some thin polypropylene socks and wear them in layers. That is the best way that i have found to keep my feet dry (and warm). Works great for me during subzero nights in the mountains. Then when the thaw comes, go to Cabellas, Bass Pro Shops, REI, wherever and get the winter boots on clearance for next year.

The warmest boots I ever had were those snow mobile boots with the heavy felt linings.