Here are some related links:

If you are a US citizen, you need to do the adoption procedure all over again by following the HAGUE Convention and then, sponsor the child green card immediately after the adoption (not need to wait). The following are US Government official websites for your reference:

http://adoption.state.gov/hague_convention/overview.php

 

http://www.uscis.gov/portal/site/uscis/menuitem.eb1d4c2a3e5b9ac89243c6a7543f6d1a/?vgnextchannel=a22c741b78c73210VgnVCM100000082ca60aRCRD&vgnextoid=a22c741b78c73210VgnVCM100000082ca60aRCRD