My 4 year daughter cries for my stepmother! help!?

Spend more time with your daughter. Start the seperation now. She will always love her grandma and want to spend time with her. But if you start taking care of her more and acting more like her mother she will start to feel that way about you too. Don't let it hurt your feelings. It will be ok. Its not going to severly mess her up if that's what you are worried about.