Need some who can program a site like Craigslist

I am starting up a nonprofit organization that seeks to help those who have lost jobs, homes, and 401k's in this current economic crisis. The organization is called "Check on Your Neighbor," and it's goal is to try to match people with needs, with people who want to help. The program that I need designed is like Craig's List, where people can initially anonymously transact business with others within their own communities. But instead of buying and selling products or services, people are on the site to state a need, while others are on the site to fulfill a need. This is a rough idea of the concept.

Require anyone who can help me design and launch this program on the Internet for a price that would not be too exorbitant