Aide avec Access 2007 (Descriptif en Anglais)

I am looking to develop a database to help me with prospecting for customers. Part of the prospection operation will be subcontracted to a 3rd party. The database exists but I need some help with adding some functionality

I need the VBA code that will allow me to

a) Add a unique ID to the each data record that is added to the MAIN database by the use of a form (which exists)

b) Select the next N (eg 50) records from the MAIN database that have not yet been selected and export them to a new database (NEW) whilst updating a flag/code in the current database (MAIN) so that they will not be re-selected the next time

c) Re-import the data into the MAIN database from the NEW database incorporating data that has been added to fields that were originally empty