Translation

The thing is that I have to say thank you to my japanese teachers and I want sth. sounds like that:
I really thank you for this year of teaching us, students, Japanese here (in my school). Thanks for gaving us time and effort. Have a safe comeback to Japan.
I really need this translaion, so hope that somebody will answer soon.
I advance, arigatou :*

I really thank you for this year of teaching us, students, Japanese here (in my school). Thanks for gaving us time and effort. Have a safe comeback to Japan.

So some Japanese teachers came to your country to teach you (and others in your group) the Japanese language, and now they are returning to Japan?

Something like:
- Kotoshi watashi-tachi no gakkou de, nihongo wo oshiete kudasatte arigatou gozaimashita. (Thank you very much for teaching Japanese this year at our school.)

- Tema to jikan wo oshimazu oshiete kudasatta koto ni kansha shimasu. (I thank you for teaching us sparing no efforts and time.)

- Ki wo tsukete kikoku nasatte kudasai. (Please take care on your way back home.)

....in very polite speech :)

I'd add in between
"iroiro gokuro kakete otsukaresama desita"
It must have been tiring for various hardship we imposed upon you.
A common saying.

"Gokuro" is not a good choice of word when a student is talking to his teacher.