In a large heavy skillet, combine flour and oil until smooth. Cook and stir over medium heat until flour is a rich deep brown. Add onion, green pepper and celery; cook until vegetables are tender, 5-6 minutes. Add garlic; cook 1 minute longer. Stir in next 6 ingredients. Cover and simmer until heated through, 4-5 minutes. , Add shrimp. Simmer, uncovered, until shrimp turn pink, 5-6 minutes. Discard bay leaves. Serve with rice.