I use following trick to set a separate location for my firefox bookmarks file. I always set the bookmark location to a drive other than windows drive, so that if windows got corrupt or I hv to reinstall windows, I never loose my ff bookmarks.
Just export ur ff bookmarks as Lunky_Star and kaustav suggested for only one time and save the file to a location, which is safe. Then type
%appdata% in RUN dialog box and goto:
\Mozilla\Firefox\Profiles\random_character_and_numbers.default
now open
prefs.js file and add following line in the end of this file:
user_pref("browser.bookmarks.file", "E:\\Setup\\bookmarks.html");
Here, "E:\\Setup\\bookmarks.html" is the location, where I hv stored the bookmarks file, change it to ur location and make sure to use
\\ instead of
\.
Now ff will automatically use the above mentioned file for storing ur bookmarks and u'll hv to never take a backup of ur bookmarks.