Here is how you can meet your new Japanese friends

1. Go to Roppongi bars

Japanese are friendly (in general), specially girls in Roppongi.  It is well known that girls in Roppongi come to get picked up by foreigners.

2. Go online

I have meet many at tbr.worldfriends.tv, unlike traditional dating site you can talk to Japanese friends for free under the title of being pen-pal friends / language exchange friends.