Alternate interface for existing website database

We currently have a database based website designed predominantly in php. Being a recruitment firm, the database stores information about our current & potential clients & candidates. We intend to get a completely web based interface developed to this existing database which will enable us to add, edit, search, amend etc. from the database. This new database would be separate from the current website & the outdated backend currently being used to access this database. The new database interface should not effect the existing website & the backend in any way. Slight modifications may also be needed to the existing database to store a few extra details but that will be decided in due course. Further details would be provided upon bidding. A live online presentation can also be conducted to take you through the current website structure.