Well, we had our son's in the community room in our building. We had too many people to do it in our apt and the thought of having it at a restaurant weirded me out. My cousin did her son's at the Carlyle. I'm sure any hotel has a party room to rent out. If you are a member of a synagogue, you can try that. Or even the 92nd Street Y might have a room that you can rent. Good luck!
Re: nyc bris location - preferrably on UES