Access-Driven Online Database Completion

Our ASP guy has been taken ill, and we need someone to complete a customer CRM system asap. (The rest of us here are PHP people). The database holds marketing information (address of marketing location, nearest depot, table of visits by marketing to marketing location and how many sales were made) and is mostly complete, however we need the authentication so that the remote depots can each log into the system. The authentication needs to be granular (ie, individual attributes can be set for each user by an administrator), and based within the database itself (Access I'm afraid - the end client doesnt have an SQL server available and has specified Access as part of the specs). A single depot can only view + enter locations/sales that have been assigned to that depot. Permissions needed are: Ability to add/remove users Ability to add/remove locations Ability to add/remove location types (school, college, university, etc) Ability to create sales reports Ability to assign a location to a user Ability to view sales reports that are outside of their own depot (ie, head office needs to view all reports) Additional features that still need implementing are: Tracking of changes (each change that is made to the database needs to be written to a file that can be downloadable by an admin) A general tidyup of the code (consistent fonts, etc).