stuffed pepper soup recipe

1 pound ground beef or turkey 1 large onion, chopped 1 green bell pepper, chopped 1 red bell pepper, chopped 3 cloves garlic, minced 1 (14.5 oz) can diced tomatoes 1 (15 oz) can tomato sauce 1 (32 oz) carton beef or chicken broth 1 cup cooked rice 1 teaspoon dried oregano