According to the CDC, it's highly unlikely but not completely impossible for a squirrel to carry the virus:
Small rodents (such as squirrels, rats, mice, hamsters, guinea pigs, gerbils, and chipmunks, ) and lagomorphs (such as rabbits and hares) are almost never found to be infected with rabies and have not been known to cause rabies among humans in the United States. Bites by these animals are usually not considered a risk of rabies unless the animal was sick or behaving in any unusual manner and rabies is widespread in your area. However, from 1985 through 1994, woodchucks accounted for 86% of the 368 cases of rabies among rodents reported to CDC. Woodchucks or groundhogs (Marmota monax) are the only rodents that may be frequently submitted to state health department because of a suspicion of rabies. In all cases involving rodents, the state or local health department should be consulted before a decision is made to initiate postexposure prophylaxis (PEP).
http://www.cdc.gov/ncidod/dvrd/rabies/Ques&Ans/q&a.htm#What%20animals%20get%20rabiesSorry about the vile sneak-attack on your daughter - it may be time for the human-squirrel Cold War to escalate to something more final...