When you say she is crying for extended periods, are you going in and soothing her? When we did the transistion from cosleeping to crib sleeping, we tried a lot of different ways….I even got into the crib with my son to try to calm him down! We did a mild form of CIO, I’d put him down in the crib and I’d put his music on and leave the room. After 5 minutes of crying, I’d go back in and calm him down, then leave again. It is a long, long process. I ended up having to lay on his floor, with my hand through thr crib, so he knew I was still there. We found this to be the most effective way to get him to fall asleep in the crib. Also, the whole CIO thing doesn’t last very long if you do it the right way, I think we were done after a week. My son has almost always been a good napper, but we did start using the crib at the same time for naps as we did for bed time. At that age, children need a strict bedtime routine.