Several 3rd party companies make disk repair and data recovery tools for Mac OS X. Search the web using a search engine or look at a software web site like www.macupdate.com or www.versiontracker.com to find a tool to fit your need. One word of warning is that older versions of disk repair utilities should not be used with hard disks or other devices formated with the Macintosh Extender Format a.k.a. HFS+ as they can actually do more damage than repair having been designed for HFS Standard formated devices. Don't just use what you have lying around make sure you have updated to the latest version!