Preheat oven to 350 degrees. In heavy skillet, heat oil over medium heat. Add o nion and garlic, green peppe, garlic and celery and saute until translucent. Ad d beef, salt, pepper and Worcestershire sauce. Cook until browned, stirring to break into small pieces. Stir in soup, sour cream, 1-1/2 cups cheese and cooked macaroni. Mix just until combined. Pour into 2-1/2 qt casserole. Sprinkle with remaining cheese. Bake 30 minutes.