Go with Elizabeth's advice: talk to counselors at your school. They will do the leg work.
Rotary Club and (I think) Lions Club help people to do foreign exchange. There are many others. Google for them (or let the counselor).
At the private HS where I used to work, there was no requirement for any Japanese language to be accepted as a foreign exchange student. Sad, but true. You will get lessons at the school, however, but I wouldn't let that stop me from studying now.