I actually believe ICA in these tapes when she says she wants Caylee to come home. Obviously she knows she won't be coming home, but, deep down, there is a tinge of guilt coming out, and she probably wishes she could take back the entire moment, beginning with her fight with her Mom, and the rage that ended Caylee's life.
Her crying is probably out of frustration in that she knows Caylee won't be home, she cannot take back what she's done, and, now that she's in custody, she will be punished for it.
It's so sad on so many levels.