Janet Murnaghan tells The Associated Press that Sarah still gets support from a machine that helps her breathe.
Murnaghan says that in the last few days Sarah has started to walk around the hospital with the aid of a walker and has even gone outside briefly.
The Newtown Square girl with end-stage cystic fibrosis received the transplants at Children's Hospital of Philadelphia after a federal judge intervened in her parents' lawsuit challenging national transplant rules.
Sarah's first set of adult lungs failed after a transplant June 12. A second set was transplanted three days later.