i would get someone to confirm this before you give it a go because if im wrong it could mess your stuff up (if not backed up) but the upgrade script for 1.1.2->1.2.2 might work? im assuming 1.1.2 was a bug fix over 1.1.1 so i wonder if it would work?
if not then you can always grab the tagged version of 1.1.2 from the
SVN (
http://code.zikula.org/core/browser/tags/Zikula-1.1.2) perform that upgrade which will take you from 1.1.1->1.1.2 then from the downloads page here you can get the 1.1.2->1.2.2 upgrade,
FYI 1.2.3 should be out shortly (matter of days or less)