P.R.
Do you have a rocking chair in her room? If not you may want to put one there. Explain to her you will rock her while you read her a bedtime story. Once you have her ready for bed pick out a book, let her snuggle in your lap and rock her while you read the story, or the chapter of a story in a chapter book, then tuck her in, give her a kiss, turn on the night light and some soft music (they have some wonderful lullaby tapes), and leave the room with the door slightly ajar. It may take a few nights but she will get the routine down and snuggle with her favorite toy while she drifts off.
It is tough but maybe you won't start this same process with the new baby.