As Australia does not do private adoption, you might be stuck with attempting to adopt (if no program already in place that you can be assesed etc).

Immigration- are there any categories that she fits in order to immigrate here? Any family members here? What supports does she have in home country? Does she need medical treatment? There is an 'Australian visa wizard' thingy on Department of Immigration & Citizenship where you can search for appropriate visas.

that's all i can think of for now,

take care,

Kate