divorce

I am married to a Chinese women now. I moved back to the US after living with her for a year. We where married in 2005. The marriage was a mistake. According to China divorce laws if both parties have not lived together for two years or more the marriage is null and voided. It will be two years this October and we have not been in contact . How can I contact the office in China to record as and get a copies showing the divorce is final .
Thanks