Schools normally promote from in-house staff. Depending on your qualifications and ability to adjust to living and working in China this could happen within a few months. Some people love it here and get along very well, some find it hard to get used to the Chinese way of doing business.
Most new managers start out as General Assistants teaching a half schedule and helping out in the office and then move up to Assistant Location Manager, Location Manager, and then City Manager. There are also possibilities for positions as teacher trainer or in the head office if you have specific talents that Aston is looking for.