Will the woman of 45 ever reach 50? Will you? Will Joanna Banana, from child star to housewife kvetch with a crock of obscenities and hostilities running out of her mouth? ""I AM STANDING IN THE MIDDLE OF MY LIFE WITH NO CENTER."" That center having been the marriage to Jay, the three boys she raised, the dishes she washed now dissolving into--what else--talks with a shrink, Dr. Lipschitz, and her two imaginary friends, Ruby and the lady from the supermarket. She also conducts an incessant monologue about her unpleasant and ugly sex life and unliberated revulsions (although Bonnie Bluh is that Woman to Woman militant) as she leaves Jay and has a couple of lovers and finally finds herself back home--relieving the monotony by spitting in the meatloaf she's cooking up. ""I am watching an outdated movie and I'm in it."" Would that it were Dorothy McGuire in Claudia.