To learn about the education system in Germany, city of Bonn has information in English.
As you are probably aware, school is mandatory for all children in Germany and homeschooling is illegal. There appear to be some exceptions for homeschooling - those who are hear with the US military or an embassy and will be here only a couple of years can probably get an exception, but anyone else must attend school in Germany. On the positive side, there are a wealth of schools to choose from in the Bonn area, and because of the laws, all children are also eligible for support services no matter what their status in Germany (diplomatic, illegal, etc.).