Hostess Anne Robinson of the new hit TV quiz show The Weakest Link on NBC may come on like a tough schoolmarm, but has her own quite vivid story to tell, of a long struggle against alcoholism and despair, and NAL's Louise Burke won a recent auction for it. It will be called Memoirs of an Unfit Mother, and British-based agent Ed Victor made the North American rights sale, for about half a million dollars. Robinson has had a notable journalistic career in her native England despite her bouts with the bottle, as a reporter covering the struggles in Northern Ireland and later as a noted consumer advocate on TV. Burke, who says that the book, "like Anne herself, is filled with insight, honesty and humor," plans to publish in October, while the show, it is hoped, is still hot.