I can see that everyone has different ideas and things to try (like I'm about to go to the opposite extreme of the above post and wrap my feet in as much Thinsulate as I can buy; I'll know the results the next time it gets cold here...)
Word of caution here, though...
maybe ditch the thick boot socks and only wear normal athletic tube socks
Most athletic tube socks are 100% cotton -- the absolute wrong material to use when trying to stay warm, especially if your feet sweat at all. There's a reason the old saying "cotton kills" has stuck with us. It will not wick away the sweat from your skin.