Good luck to you. It will be a long road, and I don't know who to recommend, but you can also have him identified through your local school district too. You will always need to have private therapy too, but you may qualify for some of it to be covered at school starting at age 3, especially since his delay is sever.
One caution, if you have not had the developmental aspect ruled out by a Developmental Pediatrician (found at children's hospitals-NOT regular pediatricians) then to be safe, I would do so. You do not want to find that your information was wrong when he is too much older, early intervention is best.
If your insurance is through a "self insured" work place, you may have more of a battle than if not. Self insured companies pay insurance companies to administer the insurance only. These companies have a loophole for some insurance regulations and will rarely if ever cover speech, or related services. The Senate is dealing with insurance discrimination for Autism right now and has put some language in the health care reform act, but it is unclear to me if the self insured loophole is closed by this, and no one knows if it will ever pass.
Good luck, keep fighting, but always pay for the service he needs so that he makes the kind of progress you want to see.
M.