Tina,
The default local Address Book is the "names.nsf" file in the "...lotus\notes\data" directory. If you are on a shared machine, typically the Personal Address Book is shared among all the users.
If you are on a shared machine, one thing you can do is make a copy of the names.nsf and name it anything other than names.nsf, e.g. 'tina.nsf'. When you're back in Notes you can go to "File...Preferences...User Preferences" click the "Mail and News" tab. Then under "Local address books" you can add a comma ',' to the end of 'names.nsf' and add the new address book name, e.g. "names.nsf, tina.nsf". This would allow the type ahead feature in Notes to include the new address book.
Note: If you 'Copy to Local' to add a contact from a Public Address Book, the entry will only go to the 'names.nsf' file. You would need to populate your personal address book manually.
Ron