Name this book

[funkychunkymonkey]

what is this book called? It was about this little girl whos mom married a guy with 2 kids. She ends up sharing a room with her sister and sleeping in a trundle bed. Then she tries to take over the attic but the boys turn it into a work out room so at one point she ends up sleeping in the bathtub in her sleeping bag. In the end the step dad makes her a room in the basement. ANyone know? I was telling DC 12 about it and she wants a copy.

I found it, took some hunting. its my mutant stepbrothers