Mass Mailing And Devloping New Leads

I am looking for a freelancer to assist me with a mass mailing project. The purpose of the mass mailing is to promote a product or service to potential customers. I have an existing mailing list that I will provide, but I also need assistance in developing additional leads. The goal is to reach a wide potential customer base. If you are able to develop a new list and create an effective mass mailing campaign, I would highly appreciate your help.