Priscilla suffered a leg injury a week ago. At the time, she was able to stop the bleeding on her own and decided not to go to the hospital because her injury was not that painful. However, as the days passed, Priscilla's wound began to putrefy, and blood flow to her leg was eventually cut off. When her leg began to turn a greenish-black, she finally went to the hospital, where she was diagnosed with gas gangrene. What course of treatment is most appropriate for Priscilla at this point?