We moved our DD1 into her own bed in her own room before the baby was born. When she wakes up, she gets out of bed and comes into our room.
That said, the new baby won't make much noise during the night as long as you take care of his needs quickly. We put the newborn between me and a bedrail and my older daughter between me and my husband. When my third one comes, someone will have to sleep next to my husband to make room for the new baby.
The only real problem is if you ever have to turn on a light for a messy diaper. I kept a flashlight nearby and that helped a little.
Good luck!!!
Meliss