There will be need for a new word. Presumably, we shall have to call her a Stateswoman. This is the suffragette's dream come true.
London's Evening News (July 21, 1960) (On Sirimavo Bandaranaike's election to Prime Minister of Sri Lanka, the world's first elected female head of government though other women heads of state and government and other women political leaders had been referred to as statesmen.
Other former Presidents have struggled with less success to use their special status and experience for the common weal. Most have written memoirs, some have striven to be elder statesmen while shunning real risks, others have turned to golf or (in the case of Teddy Roosevelt) strenuous feats of hunting and exploration. Jimmy Carter has not flinched from risk-taking and has played a crucial role as an honest broker, most notably in spurring nuclear talks with North Korea but also in civil conflicts in Ethiopia, the Sudan and Liberia.