Export Outlook for Mac 2011 mails to Postbox Windows

Question

How can I Import emails from outlook 2011 that I run in macbook pro to postbox that is installed in windows system. I have almost 10 years worth of emails saved in outlook 2011 and have managed to save and arrange each mail in particular folders. How can I transfer all the emails safely from outlook 2011 to postbox windows along with the folders.