The reason why she is searching for "WondLa" is because, back in the Sanctuary Eva had this "secret room" that she kept stuff in. Most of the stuff was little toys Murthur had given her, but one of them was a little scrap of paper showing a man, a girl, and a robot. They were all smiling and holding hands with each other, at the top of the paper the words were faded so all you could see was WondLa.
I fell in love with this book the second I started reading it.
I hope you like it that much, too.