Hi, I am also planning on taking my helper back to Oz with me in August. My plan was to apply for the visa beforehand to avoid the risk of running into an unreasonable immigration officer on arrival into Oz. I was going to say on the application that my helper was coming as a tourist as a reward for all of her hard work over the past year.
Whatever you do don't apply for a working visa for her as you/she would never meet the criteria.