There are two different telephone numbers for the emergency services in Germany. If you dial 112 you'll be put straight through to die Feuerwehr, the fire brigade, and der Krankentransport, the ambulance service. Dial 110 for die Polizei, the police. Both these numbers can be dialled free from any public telephone. The usual practice applies - state your name, location and problem.
In many of the newer phone boxes you'll also find a separate handset next to the usual phone that connects straight to the emergency services. Turn the handle to green to reach the police, or red for the fire and ambulance services. To describe your accident you simply use the word Unfall, accident, combined with other descriptive words e.g. Autounfall for a car accident.
If you are in need of a pharmacy or doctor outside normal working hours than you can call 011500 and the operator will find you a local service. In the more remote areas of the country, there will sometimes also be a local number for medical emergencies. However if you dial the usual 112 the operator will put you through to the most appropriate place.
For lost personal property, your best bet is to go to das Fundbüro, the local lost property office. There should be one in most towns and cities. If you think your property might have been stolen, you should go to die Polizeidienststelle, the local police station, to report it.