Melt 2 tablespoons margarine in saucepan, over medium heat. Add onion and garlic, cook stirring occasionally for 1-2 minutes. Transfer to blender. Add red peppers, cover and blend until smooth, in same saucepan melt remaining margarine. Stir in flour, gradually stir in evaporated milk and broth. Cook, stir constantly until mixture comes to a boil. Stir in red pepper mixture, salt and pepper. Heat through.