Need help...what can i do?

My case is a little bit special. My husband is a U.S.A.citizen, and I am a green card holder. We are willing to adopt 2 girls who are 12 and 13 years old. What make me confuse is about the two kids' status. They illigally came to U.S.A from Canada(They are born in HongKong, China). My question here is whether I am able to adopt them in USA, or I need to send them back to their home country and then apply to adopt them? I need to make it clear before making the decision....By the way...I realy love these two girls..We have one boy only. Thanks a lotttttttttttttttttttttttt.....