Jennifer Garner performed a dramatic at-home exorcism on booze-soaked ex Ben Affleck before carting him off to rehab! “Jen is a very religious person and she’s at the end of her rope with Ben’s endless screwups,” a source close to the “Alias” cutie tattled to The National ENQUIRER. “Her spirituality has helped her through the most difficult times. Now she’s hoping it can do the same for Ben!” Ben received an at-home delivery of what appeared to be alcohol on Aug. 20. Two days later, the actress arrived at his L.A. home armed with a Holy Bible, according to insiders. Read on for details of Jen’s angelic intervention, and click here for more news of celebrity rehab….