I would suggest that you think twice for the application, since I hear that the average Gmat of Austin(Chinese Student) is around 740. Your score is a little below the average.
You can get essay topics from each school's website. Usually schools will release new topic around beginning of Sep. Most topics won't be changed. Even it does change, preparing last year's topics still help you very much this year.
Thank you for your advice. This is my first time to apply at such an embarrassing age. I work in Guangzhou. Anyone who would like to share your application experience with me, pls contact me via email: cathychina@163.net