Combine first 4 ingredients in a small bowl; stir well, and set aside.
Chop bell peppers; set aside. Heat oil in a Dutch oven over medium heat. Add onion and carrot; sauté 8 minutes or until vegetables are lightly browned. Stir in bell peppers, tomato paste, and next 4 ingredients (tomato paste through garlic); cook 5 minutes, stirring frequently. Stir in rice, water, and broth, scraping skillet to loosen browned bits. Bring to a boil; partially cover, reduce heat, and simmer for 15 minutes.
Place broth mixture in a food processor; process until smooth. Return puree to pan, and stir in 1/2 cup milk, 1/4 teaspoon salt, and black pepper. Cook over medium heat until thoroughly heated (do not boil). Ladle bisque into bowls; top with sour cream mixture.