My daughter was born a year ago and we did not know she had SWCAH. She was only in the hospital 5 days and mostly due to the fact that she had jaundice, not the CAH.
Be sure to get a PEDIATRIC ENDOCRINOLOGIST. This will be the person who will be treating your child's CAH and you will be spending a great deal of time visiting them. Also, you may want to make sure your PEDIATRICIAN is familiar with CAH. Mine was not but she and her partner have really studied and read about it and are great at treating my daughter.
I breastfed my daughter for 9 months. I gave her the medicines in a small medicine nipple made by MUNCHKIN which I found at the drug store. In fact, we bought a lot of them and I still use it for her meds. I was told to express brestmilk to give her the salt. I ended up supplementing my daughter with formula but you don't have to.
Also, visit the Cares Foundation. They have a wealth of good information. You can call them and they can help you gain information about CAH.
The most important thing is to educate yourself and become the advocate for your child. You are the only one who can give her a voice right now. Do what is right for you and your family. You may have to help educate your doctors depending on where you live. There are no other cases where I live and like you my husband and I did not know we were carriers nor is anyone else in our family affected by CAH.
Congratulations and enjoy your new little miracle!