You're local dealer 'should' help you out at no charge. You'll need ot give them your vin# (mostly to assure ownership) and your radio's serial #. Also, you can go directly thru Becker directly using their online service, but they DO charge $30 for it.
Here's a link to their code request form:
http://www.beckerautosound.com/Code_request/Code%20Request%20Form.htm