Kay's advice is really good, though you might want to look into the research done on electric blankets. The soft plastics encasing the wiring and the ... flame retardents, I believe - have been linked to serious health effects like cancer. I steer clear. A snug hat works wonders, since the head is of course where a lot of the body's heat escapes.
Also, night visits often signal a high-need time, according to Dr. Sears. Your daughter is probably noticing that something is up with Mommy. Even if you're not sick or feeling especially different yet, our kids are master readers of us. So, she might be feeling some extra need for closeness now. While you spend extra day time cuddling, and wait for the positive effects at night, you might consider bringing a sleeping bag or mattress or something to the foot of the bed or otherwise near the bed so she can sneak in but be aware of boundaries.
You can make sleeping in bed with you a reward for sleeping in her room or on this special "bed" in the room wiht you. Dr. Sears suggests that after X nights in an agreed bed, she can sleep all night with you, then after a short time graduate back to her bed, and at that time you can introduce a special new bear or soemthing to celebrate (and of course help her settle back in).
L.