I don't mean to criticize, but unless you are looking for a very meager Continental Style Breakfast, under 15 bucks is unreasonable. You plan on breakfast, coffee, juices and water service....plus staff/labor....for you to park your group for 2-4 hours while you handle a business event?
i hope some one comes in with a recommendation for you, but unless you provide more specifics on what your looking for, the only places that would fit the bill are diners.
Do you need an actual closed room? If a private area will do then I would suggest
The Original Pancake House
817 Bloomfield Avenue
They have an area on the right side when you walk in that they could probably set up for you. They have very good food and service. You could call and ask about what they could offer for the $15 pp.