Just how much can we handle

Recently, Shawn and I recieved custody of Haylea and Tina... we had Larry to, but the court system gave him to his dad. So lately we have had to convert out garage into a bedroom for the girls, complete with carpet, bunk beds, dressers, and even posters on the wall to make it "homey." We have 6 people living in a two bedroom house.... well now with the garage a bedroom I guess you could say three bedroom. Bryanna and Allen both cry out during the night, so to keep one from waking the other, Allen is in our room with his baby bed, Bryanna has her room with her toddler bed, and the girls have the garage. We stay busy, with me working and going to school, Haylea has high school and the homework load that comes with that plus marching band on top of it all. Tina started a new school because we live in Hartford and can't afford to drive her back and forth to Southern all the time, and has now asked if she can do gymnastics or basketball, both of which change depending on the mood. Then you have Bryanna and Allen who are always running around doing this or getting into that.... However, we are doing fine, we take things mostly on a day to day basis... who has practice, whos going to be late for dinner, whos in the shower now, what time is- crap you should have been in bed an hour ago... but yeah, we are functioning.
However, Wendy calls today asking if the court system takes Larry away if Shawn and I will take him back.... I asked if there was anyone else.... the response is "no, so are you going to take him or are you going to send him to foster care?" What am I suppose to say to this?!
Shawn and I are just starting out our marriage, we have two young kids, the two girls, and she doesn't understand that we are pushing the limit, both on living space, and sanitity.
There are days I dont know if I will get to sleep, most nights I dont get to before 11 or 12, just to get back up at 5:30 and start all over again....
I've talked to Mom, and of course her house wont pass, Wendy says Mamma isnt a blood relative so he cant go there, Heather and Timmy and Noah are still trying to figure out this new way of functioning.... so Shawn and I are the only ones left.... I guess thats the answer... of no, theres not anyone else....