[wasabijuice]

The International Studies degree will help if you take an Asian studies minor or concentration along with Japanese language minor with of course at least 1 semester abroad in Japan. Nowadays they don't want whiney JETs who need their hand held for every little thing. Outside of teaching in Japan or somewhere else, I don't see the degree doing very much for you. If you dream big you can apply for foreign service, but that competition would be tough, unless you are stellar.
You can always come here and teach, see if it is for you. Then go home and get an Education degree in 18 mos or 2 years. Maybe if your Japanese language skills are really good you can get in with a Japanese corporation, clerical, or something back home.