just some short informations: You have to learn German in order to work in Germany. You also need to make sure that your degree is recognised by the Landesprüfungsamt of the state that you will live in (thats the instituation which makes sure that your degree fulfills the requirements to work as an OT in Germany). After that process is finished successfully you can apply for a German OT certificate (in German "Berufsurkunde") - without this certificate you won't be allowed to work as OT in Germany.
You can find lots of information on OT in Germany (including job offers) on this websites:
(including an active forum with OTs all over Germany)
Currently there is a big shortage of OTs in Germany - so after going through the approval procedure there is a fair chance in finding a job!