People, kids included, acclimate to the temperature they are used to being in over a period of time. We have found that 72 or 73 is good for our house (sometimes 74 if it is really cold or windy out). Our house is pier and beam with no insulation in the floor, so the floor stays cold. The walls and ceiling are well insulated, we did that when we rebuilt the house after Hurricane Ike. Though our house is not nearly as drafty as it was before the storm, that cold to the floor can chill you down. We have all hard surface floors, hardwood and ceramic tile. We wear house shoes or socks around the house.
Check her at night to make sure she is not cold. Check her hands, feet, head. If you check on her at night and she is curled up in a little ball, she is probably cold. Our bodies do that naturally to try to conserve heat.
Make sure she sleeps in footed pajamas. You can add socks and an undershirt underneath her pajamas for extra warmth.