I think at Himeji-jou, Japanese people offer to guide
Westerners through the castle for free as a way to
practice their English. I don't know if Himeji is too far
for you to travel but it might be a good option.
Another option might be to start a social group. If you
have 3 or 4 friends who are willing to join you, all you
have to do is put a message on an English site offering
cross cultural exchange in Osaka. Keep it low key. Just
meet at a kissaten for an hour on a Sunday.
It may be you and your friends for a while but keep
advertising and keep turning up.