Applying and TEFL Certification

Hello. I am a certified elementary school teacher of 9 years in the US and am interested in teaching English abroad for the 2016-2017 school year. When should I apply for a 2016-2017 position? Also, I am currently certified to teach and have taught ESL in my current state and would like to know how the TEFL certification process works. Do I need to obtain the TEFL certification before applying for a position?