There are German language classes at MPIA (contact?). If you want to improve your German you can also consider ordering a "Sprachzeitung", i.e. a collection of current newspaper articles with some help for the more advanced vocabulary. There is one from Schuenemann Verlag called "Presse & Sprache" (you can order a free test issue without any obligations from the website). Another one is "Deutsch perfekt" from Spotlight Verlag.