If I understood your question, this should work for you:
/home/your-user-name/.mozilla. Inside the .mozilla folder you will notice a firefox folder. Look inside the firefox folder for your user profile folder, it will have a series of numbers and letters (something like this:
u7qqadwy.default). Inside that folder you'll see a folder called
bookmarkbackups. Open the backup's folder and you'll notice a few different files which will be named with a date and a json extension on the end like this:
bookmarks-2012-04-13.json. Simply copy the latest few dated files to your new profile and place them in the same firefox directory. You'll need to open Firefox and go to Bookmarks-Show All Bookmarks. From there click on the import & backup link. You'll get a pop-up window that should open in the same directory you pasted the old bookmarks into. Select the latest one and choose import. You'll now have your old bookmarks in the new profile.
You can do the same thing if you have saved passwords. Just go to the
.mozilla folder open your profile folder again and copy the
signons.sqlite files. Paste those files into the new directory over-writing the old ones and restart Firefox.