Grrrr. Very frustrating.

DS is the same age as your DD. He went through a patch (read months) of getting up multiple times. Like you we tried reasoning, bribes, yelling, putting him back, shutting the door etc.

Now I sit in there until he goes to sleep. It is the only way that he will stay in there. I don't give him any attention, just sit there like a statue. The plan is to get him going to sleep quickly with me in there (which is starting to happen) and then I will start moving away from the bed, then out the door.

Good luck. I know it is hard to manage when you have the baby too.