Let me start with a great big <<<<<HUG>>>>>>
Ok, let me ask you this, when she goes to sleep in the carrier, is she rocked to sleep? Or can she just fall asleep on her own, without movement?
Honestly, there's nothing wrong in itself with letting her sleep in the car carrier. It's actually recommended for reflux babies. What you will want to do is let her sleep in the car carrier, but put the seat in the crib, so it becomes familiar, and she understands that this is her "bed" area. You can worry about transferring her over later if you wish, or you can start now. Try raising her matress to a 20-30 degree angle to simulate the seat. I would recommend getting or making a sling to put in the crib so she doesn't slide to the bottom.
However, if you have to rock her to sleep or use any other prop every time you put her in it, then this is a habit you'll eventually want to break. At her age pat/shh is recommended. There will be crying, but as long as you are there with her she won't feel abandonded. Babies need to cry to learn independant sleep; it's a taught skill, not one they are born with (although some learn faster than others). Anything that is taught takes time, fortunately it can be taught in 3-4 days with most babies up to about 5-6 months of age if you're consistant with the method.
Keep your chin up, you're doing fine
*HUGS*
Sonya =P
