Quantal has 3.6. I feel that the new version is heavier - at least for my specs. (Beside having this problem).
How could I install an older version of LibreOffice?
I haven't done this, but you should be able to
Source for the full list of older LibreOffice versions is this ask.libreoffice answer.
Old (and magically also most new) versions at:
Be careful to download from /deb folder.
well done! libreoffice is installed!