You need to consult with an attorney immediately if your divorce is not yet finalized. If your divorce has been finalized, there is little you can do at this point if the child has already been adjudicated to be a child of the marriage. However, you should be entitled to contact if the child has been adjudicated yours. If it wasn't provided for in the final judgment (presuming its been entered), you would probably need to do a modification. I would really need to know more information though about the status of your matter and what has transpired up to this point in order to be able to answer your questions fully.
My office offers free initial telephone consultations if you would like to discuss your situation in more detail, as well as your potential rights and options. If you would like to schedule a free consultation, please contact my office at 407-971-6140.