485 RFE: proof of the legal termination of the marriage

大家好。我现在收到485 的 RFE. 内容如下：

Submit proof of the legal termination of the marriage(s) of XXX （me) and XXX (My ex-hu*****and). Such proof would normally be a final divorce decree, death certificate, marriage dissolution or other such documentation. In order for the legal termination of a marriage to be considered valid for immigration purposes, it must have been registered with a civil authority.

我以前在中国离的婚（2002年9月）， 手头有一份复印的离婚证书 （民事调解书），然后再2009年12月与现在的丈夫结婚， 后来来到美国。 请问具体这个proof of the legal termination of the marriage怎么搞？ 需要请律师来办么？

不胜感激。