The shuttered La Renaissance Banquet & Conference Center in East Windsor has been purchased by a church for $ 1.45 million which plans to renovate the deterioriating structure for its services. The Crossroads Community Cathedral intends to use the 27,500-square foot for its growing congregation, drawn from north central Connecticut and south central Massachusetts, according to Thomas Wilks, an agent at Clemens & Sons Realty Inc., who listed the property.