For some general information about the health care system in Germany, look at AngloInfo. They have information on emergency care, giving birth in Germany and a medical glossary. For the appropriate number to call for an emergency, see http://www.gesundheitskosmos-bonn.de/notfall.htm it is a comprehensive lists for who to call in an emergency for dental care, for violence against women, for children's medical, for eyes, fire, etc.
For a local emergency or after-hour needs, there is service for private patients with on-call doctors who speak English and who will make house calls around-the-clock - even on weekends and holidays. ARZT RUF.