Dispatch Software - Asterisk PBX integration preferred

Need a web based dispatch portal, where dispatchers of a volunteer EMS organization can log calls, (name, phone number, nature of injuries, exact address, etc.) all calls must be logged to a database. The call gets dispatched over a radio system, but the responders need to be able to receive a text with exact address, and all further info. Budget is low since this is for a non-profit EMS organization, all volunteers. Please PM me for more info.