B.P.
We had our son sleep in his carseat for the first 3 months too. He would want to eat constantly and I was too exhausted to keep him upright after a meal (he would fall asleep during our breastfeeding). It worked great! That is until he started to be able to climb out! I understand your being nervous about the crib thing. Our son hated his crib at first. I reccomend a few things. Don't feel guilty about cuddling before bed. Put her in her crib for short periods of time so she sees its not a scary place. When you put her into the crib for nightime sleep have a little routine so she knows its bedtime. I talk to my son gently as I tuck the blanket underneath his body, close his door, put a fan on, and most importantly, I use the OceanWonders aquarium. It plays lullabuys and lights up. Sometime he turns it on himself in the middle of the night and falls right back to sleep. I don't think a screaming child will fall asleep. Well, maybe they will eventually, but I don't think its the best way to do it. She may cry a little when you put her in the crib, this is normal and ok. But if she is screaming, then pick her up, soothe her, relax her, and try the whole thing over. The sooner you do this, the better. Try to put pillows under the mattress to slightly incline it. Works well for us.
I forgot to mention...does your daughter have a "lovie" also called a transitional item? Our son fusses until I hand him his teddybear handpuppet. Its soft and he can chew on the arms. It helps to distract him and I think makes a big difference.