Orphan adoption

Hi,
My wife and I are from the Philippines. We are GC holders. Her friend
from the Philippines called that a mother left her newborn with them
and asked us if we can adopt the baby.

I guess that we need to be US Citizen first before we can do that. In
the meantime, the baby is with my wife's parents. Shall we leave the
baby unregistered? If we register her, who would be the name of the
parents? We have a signed letter from the mother that she's abandoning
the child to us.

My wife plans to go to the Philippines every year so she can visit the
baby and once we're allowed to adopt, we will petition her. Is this
the correct approach? Is there anyway, we could petition before we get
our citizen****p? We're eligible to apply for US citizen****p in a year.

Any advise would be appreciated.

benito