Later in life
Kathy later did retire from crime-fighting and bought a circus, Kane's Kolossal Karnival, although she did occasionally still fight crime if needed, even teaming up with the new Batgirl, Barbara Gordon, on several occasions. In August-September, 1979, in Detective Comics #485, Batman followed up on a tip that the League of Assassins was going after Kathy Kane at her circus. He showed up just as she was attacked by the League, and Batman was knocked unconscious by the Bronze Tiger, who at that time was in the thrall of the Sensei, leader of the League of Assassins. He awakened to Kathy's scream and found her dead, murdered by two members of the League. Batman later tracked the killers to the the Sensei's lair and fought the Bronze Tiger and several of the league members. The Sensei and the Bronze Tiger escaped, but Batman captured Kathy Kane's two killers, avenging her death. In the post-Crisis world, it has not been established whether or not Kathy Kane ever operated as Batwoman. There is a mention in Suicide Squad #38 (February 1990), regarding the Bronze Tiger that, "They chose the Tiger to kill an old friend of Batman's--carnival owner Kathy Kane. Batman arrived, and while he fought the Tiger, someone else killed Kane."
Ghost
In February 1999, a "ghost" of Batwoman appeared in The Kingdom: Planet Krypton #1 one-shot, tying into the new "Hypertime" concept introduced in "The Kingdom" books. In the story, Batman, investigating a disturbance at the Planet Krypton restaurant, met the Batwoman "ghost" and somehow recognized her as "Kathy". Who knows? We may at some point see a "retcon" and Kathy Kane will be reintroduced into the Batman Family, as the "Girl-Gangbuster", the BATWOMAN!!!
Batwoman and Bat-Girl Home Page
For more info and pics check out The Batwoman and Bat-Girl Home Page for the Golden Age info and pics. http://homepages.infoseek.com/~treborred/Batwoman.html And for NEW Animated DC hero teams check out http://uts.cc.utexas.edu/dcu_anim/dcu_animated.html