All what you need is in..
Windows XP
C:\Documents and Settings\#####\Application Data\Mozilla
C:\Documents and Settings\#####\Local Settings\Application Data\Mozilla
Windows 7
C:\Users\#####\AppData\Roaming\Mozilla
C:\Users\#####\AppData\Local\Mozilla
*##### = is your User Account
You must backup that both the Mozilla folder, but remember DO NOT REPLACE the folder into one. backup to both separate. Before making a backup, close your Mozilla browser first.
You can test it by close your Mozilla browser, cut both the folder and paste it separate elsewhere then open your Mozilla browser. You will see it as a newly installed. close your Mozilla browser then replace it back. Or test it by copy it both then paste into the directory your wife laptop.
* Note: directory Application Data, Local Settings, AppData is super hidden folder. You need to unhide "hidden protected operating system folder". To change it, open "Folder Option" in Control Panel then change it as pic below..
http://www.spywaredrguide.com/VirtualDr/images/xp_hidden_files_and_folders_01.jpg
Apply->Ok.
~hope it helps~