Tortoise

Hello, hoping someone can help me with the following question.. I'm British and have 2 dependant children age 10 and 13. Both children are Australian citizens/passport holders. Their father (Australian citizen, born in Australia) and I are married but have been separated for 6 odd years. We both live oversees in Asia and there's a possibility he might have to return to Australia for work. He would like us to all go so that he doesn't miss out on seeing the children. I don't believe he can sponsor me. I believe the only option for me would to apply for a guardian visa which only allows me to stay there until the youngest child is 18 years. is there any other visa that I could consider?