Realizing this is an old thread, here is a link that may solve your issue.
http://stackoverflow.com/questions/3...s-to-wordpress
For a bit less technical solution, you may want to use a Joomla component such as OpenSEF or sh404SEF to export the URLs. Then, ought to be ways to extract the URLs (date/name) from the Wordpress database and match those up via Excel and mate that to htaccess redirect commands.