Note: As the Church has said, the manual has been prepared as the primary source of lesson material. These supplement, from general conference addresses, are meant only as a complement to your study on this lesson’s topic.
For Relief Society sisters:
Consider reading Presidency Henry B. Eyring's talk "The Caregiver," from the most recent General Relief Society Meeting. It has some wonderful insights and stories that can give background to this topic in the context of Relief Society.
For priesthood lessons:
Consider reading President Uchtdorf's talk "The 'Why' of Priesthood Service," from April 2012 General Conference. It gives great insights on this topic in the context of priesthood power and service.