Ask @CreweAudi for new parts or one of our recyclers for used ones.. You could place a wanted ad in Market. To do this you need to upgrade your account and pay the one off £2 fee. Click on your user name then third down on the right "Account upgrade"
Audi.7zap.com is an excellent resource for part numbers and general information, probably best to find what you need here(this is 2003 though other years there too and will likely be same).