There is a topic here
where Ladies are encouraged to share some phrases in other languages
You could post there with a few of the phrases you know in German, and invite anyone who also knows German to PM you to chat.
There is also a separate forum for the German Version of Lady Popular here
and I'm sure they'd be happy to chat with you. Since you can have a separate Lady on each server, you could even create another Lady in the German Version, as well. Participating on the German site should be a good way to get better and better with the language.