In a large skillet, sauté peppers, onions and then add garlic in butter over medium heat.
Add tomato sauce, crushed tomatoes, Worcestershire sauce, Italian seasoning, salt, pepper, sugar and meatballs. Toss to coat meatballs, cover and cook over medium-low heat, stirring occasionally. Cook for 15-20 minutes or until meatballs are thoroughly warmed.
Spoon into bowls and serve topped with shredded parmesan cheese and garnish.