these are what i have thought of so far. today i consult japanese collegue at my workplace who has had quited a firm and graduted ms of nyu. after talking with her i thought of plan c below.
a. this year enter undergraduate school overseas, study hard and get good gpa and enter grad-school with a scholarship. also with RA contract if lucky enough
b. this year enter grad-school in Japan, study hard and get good gpa and enter grad-school as master or ph.d studen overseas
her advise was i. not to spend time and money on undergrad-school, ii. not to estimate yourself too low because the master course' students' level are not that high even in u.s.
c. next year enter grad-school overseas. in order to achieve this, work and study hard this year to get good recommendation and supply the poor gpa score
though plan c is what i have been afraid to think of;;, to me it seems right in a way that i do not have a reason to cut out.