What job can I find if I just finish Polish preparatory courses?

i mean if just finish 9 month preparatory polish course,what job can i find? i have a bachelor degree of business in my country(asian country), is it useful?

You can work in kebab shops.

what else? if i wanna be a teacher,which school or uni i can teach? even available without polish uni diploma?

There are Polish people out there who speak 4 languages fluently, have double M.A.'s and are unable to secure employment in Polish academia because their PhD's ( awarded by Polish institutions ) aren't good enough or the university only hires cousins of active faculty.

You're daydreaming.

Forget about it - you're not going to get employed here as a teacher. It isn't unheard of, but you'll have to network like mad and be very, very good at seducing/influencing people.