I think you have a strong case as you have to take your younger child in that direction anyway. Play the harrassed mother/ecologically sensible card. Point out the inconvenient public transport connection or the dangers of the route your older child would have to walk. Are you in employment? Tell the authorities that you cannot keep your job if you have to visit two different sites twice a day. Rake up lots of pros and be prepared for their cons, such as:
The school you want is full up with children from its own district - respond that people move all the time, there will certainly be vacancies by the time school starts.
You are a non-working mother, you have time on your hands - respond that traipsing back and forth for two hours every morning for a four to five hour school day severly limits your flexibility regarding things best done without dragging two kids around such as doctor appointments or appointments with the various authorities or even your German classes as you want to integrate in German society.
The other school has a special German program for foreign children - tough one. Hmm. Oh, your kid is coming along fine with German, the school doctor confirmed that his skills are sufficient to join school this autumn, special schooling will not be necessary.
And children pick up languages like chicken pox, they can't help but learn them when they're in contact with German speaking playmates all day. He'll be talking circles around you by September.
EDIT:
QUOTE (kathie @ Mar 11 2008, 12:40 pm)

In theory though, the school that your child is allocated to should be the closest one to your address anyway, so they consider that as being the most convenient option.
That is not always the case. My son was supposed to go to a school 3km away instead of one 1.5km away that I could drop him off at when I took his sister to day-care. The authorities said that there were too many boys in that school already. Luckily, we moved later on that year and automatically ended up in the closer school. Sometimes the authorities' reasons for doing things are even more far-fetched than the parents'.