i haven't gone to japan yet, which is very silly for someone who has studied it for four years, so i am very very envious! i've always wanted to start in hiroshima prefecture and just go wherever the trains took me.
where did you go?
and it's a political science degree (or at least, that's one of the routes you can take) and if i were to get my masters i'd probably head in the direction of international law...big-wig bureaucratic type stuff or maybe try the political arena.
there are also a couple of options that include teaching over in japan. some official government type jobs, others are independent businesses and usually take place in juku.
as for my language capabilities, i can read and hear japanese pretty fluently now, but my speaking skills are absolute crap. i stutter and stumble a lot and forget which form goes where and it's not pretty ~_~
i've never used rosetta stone but a trick i picked up that really helped improve my understanding of japanese was to watch kid shows in the language. disney movies in particular, if you can get a hold of one of the multi-language dvds.