Is it possible to import the .rwz file into Outlook 2011 for Mac so I don't have to rewrite all of my rules?
The Mac version of Outlook uses a different format to store its mailbox rules definitions.
Short answer, no, it is not possible. In fact, it is apparently quite the headache getting into those files at all.
The closest thing I've found has been this Developer Reference page that discusses the Outlook Rules Object model