Expanded User Management Joomla 1.5

We are looking for an experienced Joomla programer to make modifications to the Joomla 1.5 User Management. 1. We need the ability to add fields to the registration process. These will be apx 10 text boxes or drop down menus. 2. We want to change the current access groups: We need to be able to assign them as: Public, Registered, Staff (Registered has access to public and registered, Staff has access to all front end pages). We do not want to use Community Builder as it is not running Native 1.5. We would prefer to use the core user manager system. We would need all files to be commented with changes. We would also need a list of all changes so that we can use this on future versions of Joomla.