Here are some JLPT resources that you can use for your professional (and personal) development as an ALT in Japanese schools. All courses have audio and much more!
Try the Kanji Flashcards and Kanji Quizzer web-based app to test your hiragana, katakana, and kanji. From JLPT N5 to JLPT N1! If you need to work on your conjugation, use this Japanese Conjugation Practice web-based app.