PHILADELPHIA (AP) -- A 10-year-old Pennsylvania girl recovering from two double lung transplants is expected to be released from the hospital this week, her mother said Monday. "We expect Sarah to go home this week! Maybe tomorrow....." Janet Murnaghan said in a post on her Facebook page. Earlier, a spokeswoman for the family, Tracy Simon, said a final decision hasn't been made on exactly when Sarah Murnaghan will leave Children's Hospital of Philadelphia. The Newtown Square girl with end-stage cystic fibrosis received the transplants this summer after a federal judge intervened in her parents' lawsuit challenging national transplant rules. Her case spurred a national debate over the process of getting organs. Janet Murnaghan said Sunday that her daughter was taken off oxygen, although she still gets support from a machine that helps her to breathe, and has started to walk with the aid of a walker, even venturing outside. "My sister pointed out that today is our Mom's birthday -- she died 11 years ago," she posted Saturday on her Facebook page. "And today is the first day Sarah has not needed any supplemental oxygen. Miracles from heaven!!!" Simon said Sarah's recovery is now focused on building her muscle strength so she no longer has to use a breathing tube. She said Sarah recovered from a case of pneumonia that stemmed from the tube. Sarah's first set of adult lungs failed after a transplant June 12. A second set was transplanted three days later. After her parents sued to change a national transplant policy that put her at the bottom of the adult list for patients 12 and older, the federal judge intervened and the Organ Procurement and Transplantation Network -- the private nonprofit group that manages U.S. organ allocation -- added Sarah to the adult list. The case raised questions among some health specialists and medical ethicists about how organ donation rules are developed and under what circumstances they might be disregarded.