As far as going to Junshin is concerned, I don't think anything more is necessary, since you're going to its "setsumei-kai (school explanatory meeting for prospective students)."
I personally think that you are not eligible for financial assistance in Japan, unless your guardian qualifies for unemployment or something (my apologies
). Also, most private schools don't offer such assistance unless you're either very smart or have a special talent (in arts or sports). You should check out Canadian educational assistance; there may be a possibility of student loan or something.
Also, if you think the tuition is too high, you should seriously consider Kokusai High School, where tuition and other expenses are only 1/4 of Junshin's. My description of the school may give you an impression of a school for nerds, but it is not. The academic curriculum is not all that stressful. Because it's public, the school admits students of all categories, coming from all walks of life. It is a healthy, eclectic mixture of students that should be interesting and stimulating.
If you're visiting Junshin in summer, you should also go visit Kokusai. The school building and facilities are new. It offers classes that are unique and not found in other "normal" schools (such as dramatic arts, Japanese musical instrument playing such as koto and shamisen, foreign language study other than English, etc.)
I think you really should give Kokusai a chance. Email them now or at least visit the school during your stay in Japan this summer. Please remember that you can apply with two or more schools. The only charge involved is the entrance examination fee. The entrance fee payment is required only when you decide to enter the school (to be paid for Junshin and none for Kokusai).
I wonder when Kokusai holds its "setsumei-kai"...
Do you know, Nagashima-san?