You would have to wait until the child is born and then file for adoption in either the Surrogates court or the family court (if they do adoptions in your county). You should both have an attorney. I would advise you to seek legal advice immediately to decide how to proceed.
I hope you found this answer helpful and if so, please let me know by clicking the "Mark as Helpful" button at the bottom of this answer. It’s easy and appreciated. You can also choose a "best answer" if you wish. This is easy to do and greatly appreciated.
This advice is not meant to create an attorney-client relationship and is a general anwer to the question posed.