Separating the Baby from the Booby:)

OK, so I am on my fourth kid and you would think I would have this down to a science.  Well, that obviously is not the case here.  My fourth is definitely a cutie but she is not a sleeper!!  And, she likes to sleep right on top of my chest with easy access to my boobs...which happens to be her most joyous comfort these days.  I am thinking that because she is the last, and because there is so many other things happening with the other 3 kids, that we have just gone with the flow.  She is totally not scheduled and she does not sleep much during the day.  I think she takes a few 20-30 minute catnaps and that's when she falls asleep eating.  The instant I move her off of me is the instant that she wakes up.  So, shhhhhhhhhhh, I just put her down in the pack 'n play and she is still sleeping:)  Now, it is 11pm and she does tend to 'sleep' through the night as long as she is on top of me with her easy access to the boob!!
Now, you might ask, don't I  know better than to let this continue??  Duh...of course I do.  And, a few weeks ago, we had her sleeping in another room in her crib for 6-8 hours a night.  Than, she had RSV and couldn't breathe and so she slept on my chest while I tried really hard to sleep in a recliner chair.  Fast forward 4 weeks and we are still sleeping in that chair.  I'm not sure if it's because she's the last one that I am holding onto this or what, but I know the time is now.  I must get her sleeping on her own and in her own crib so that I can sleep the entire night in my bed!!
Now, right now I'm too tired to even care about any type of intimacy with my husband...I just want to sleep in my bed again:)  But, how do you even try to get her back into her crib when she will be sharing a room with her big sister...who needs her sleep for school.  I'm still not quite sure what to do but there is spring break next week, so I need to figure it out really soon!!
For now, she sleeps apart from me over there in her pack 'n play.  For how long, I have no idea...but I think I'm gonna crash on the couch and she how long she goes...