It is simple , once you have SqlLite Manager add-on for FF. ( add-on, source)

Just run the following query ( for the last 7 days bookmarks) by selecting “places.sqllite”:

SELECT
"<p><a target='_blank' href='" || moz_places.url  || "'>" || moz_bookmarks.title || "</a></p>"

FROM moz_bookmarks Inner JOIN moz_places WHERE moz_bookmarks.fk = moz_places.id AND moz_bookmarks.title != "null"
and last_visit_date BETWEEN  strftime('%s',date('now','-7 day'))*1000000 and strftime('%s',date('now'))*1000000
and dateAdded BETWEEN  strftime('%s',date('now','-7 day'))*1000000 and strftime('%s',date('now'))*1000000

(OK, I must know why I multiply by 1000000  – but,hey – it works ….)