Do I need a visa o get out of China?

1. You don't need a visa to get out of China. With your current visa, you can enter China twice bofore it runs out (20 November). The visa should also states the allowed duration of stay (usually each entry allows 30 days) and you should leave China before the 31st day.
2. I think you mean ''Can I reapply when this one is still valid?'' No, once you get a new visa, your original visa will become invalid. People cannot hold two China visas at the same time.