The waiting, what is normal for the process?

We finished our classes 12/2011. Was LONG process and many delays as well (for everything). But found a teenager for adoption Dec 2012, many more delays for 2 months, and then once we met him, he literally moved in 2 weeks later. They said that was very unusual, but he was ready and we agreed. Now he has been w/us 3 weeks and I am seeing how expensive it is. Mileage in just 3 weeks over 400+, and he eats all day long. Our grocery bill has doubled (and I have 4 bio kids) but I don't want to tell him he can't eat if he is hungry. He is thin and extremely active, so not over eating. I thought we would get help with mileage costs, but none offered. Are subsidies supposed to offset that? If so, when do they start? Nobody has discussed subsidies w/us, but I see some stuff about it online.