Complex sentence: Sir Paul McCartney wanted Americans to help Americans by buying Freedom... all proceeds of his free will and choice to help out 911... he also had written anonymous checks to several of 911 victims who were New York police officers to help in medical recovery.
Split into simpler sentences: Sir Paul McCartney wanted Americans to help Americans by buying "Freedom" with all proceeds going to victims of 911. He also had written anonymous checks to several New York police officers, who were victims of 911, to help with medical recovery.