If you have access to the joists from below you could retrofit radiant heat.

Examples here:

http://www.warmquest.com/radiant-heat-applications/floor-heating/heat-existing-floors

Access from garage the floor and insulate it. Second, you could buy a heater that will fit into the wall. Third, what type of heat do you use, can you drag it to the bathroom (ducts)? Fourth, can you put some sort of a decent looking screen above your entrance door so that there is some sort of air and heat exchange with the rest of your master?

Eheat.com makes elegant heaters for a wall.

Thank you for all great ideas!
This week I am starting with the gas heat, see if I could have more forced air go into bathroom. Next step is insulation and then maybe a hard wired wall heater.

Good insulation is KEY. I reguted my home three years ago and spent good money on insulation plus quality windows. Lastnight or temperature was -11 in Boston and we didn't notice it.

When walls are opened you do it once and you do it right. Next winter you're gonna have lots of pride in what you did when you feel the comfort!