I am not familiar with Osaka or the hospitals there, but a good resource to check (if you haven`t already) is the MIJ mailing list
There are frequent questions about English speaking doctors and the like. I`m not really an active participant (as I speak Japanese and am not dealing with cultural issues - the list sort of focuses on venting) but they`re a good group of people who are generally helpful to others in the same situation.
Unfortunately, despite being married to a Japanese man I`m not really "one of them" and have experienced quite a bit of nastiness. *sigh*