Your husband hasn't objected to the child still sleeping in his bed with you? I know this sounds harsh but really that is just foolish. I am ashamed of you both.
You are not kicking her out to make way for someone new, you are regaining your space, may well be regaining the special time you and your husband should be sharing with each other at the end of the day to keep your marriage strong, and teaching her to develope independence in at least one area.
Do not make the same mistake with the second child you have made with the first one!!!! I don't know if you intend to have the children share a room but I guess it is time to put her in her bed, the baby in it's bed in the same room with her, and for goodness sake get it back together for you and husband having your own room. She won't be alone and won't resent her brother because they are together in the same room and neither one is sharing your bed.
Don't let her fall asleep in your bed then move her to her own room and her own bed. Start out in her room with with her reading, singing, rocking her, but do it in her bed with her, if she gets up in the night and comes to your bed put her back in her own bed. This is going to take some time to establish with her. (My sister-in-law had the same problem with her son. She finally had to toughen up because my brother had had enough!!!! By that time my nephew was 5!!! He came to me for advise because frankly he was ready to file for a separation.) She will wake up and come back into your bed, just move her back to her own room and bed every time it happens. Your husband is going to have to help with this. She isn't wanting her own bed and room because she has never had to have it and she wants company. After all you and your husband share a room and don't have to sleep alone, why should she??? This is why I am suggesting you put her and the baby in the same room, different beds.
Tuck her in with warm things around her as she will miss the body heat, heating pads, hot water bottles, whatever. Play tapes or CD's of water falls, or waves, or breezes blowing, as this will be similiar to the breathing she hears at night. Stay in her room with her until she falls asleep, reading softly, tuck her in, put on the noise, and then leave the room.
It is going to take a while to break this habit, it's taken 2 1/2 years to develope it.
P. R