Angela,
I think ur girl is feeling insecured, and since she has been the only child at home, she gets the full attn at home. And when she goes to sch, she clings on the TA to seek comfort..Can I know how long has she attended her sch for? I read that this phrase would be over soon, but you do need to assure her mommy daddy love you as much as before, even when there is a new baby..
Come to think of it, my son had the separation anxiety for a short while when he was about 1 year old...he would keep crying and wailing everytime we left for work. But all he could do was to keep assuring him that daddy mommy would always come home to him at night.. I find that reading relevant books to him helped alot..I managed to find many relevant books and read to him so he understands the logic that daddy mommy have to work...it helped him to get over that phrase quite quickly..
During that time, whenever we were home, we didn't turn on the tv/ handphone, and we paid full attn to him, even just by listening and talking to him..he felt important and loved i suppose..