Heat the vegetable oil in a stockpot. Add the flour, stirring constantly. Cook until the roux is dark brown; do not burn. Add the celery, onions, green peppers and garlic. Cook for 5 to 10 minutes, stirring constantly, Add the bay leaves, salt, black pepper, oregano, cayenne, clam juice, chicken broth, bouillion cubes, canned tomatoes and sausage. Bring to a medium boil. Cook for 15 minutes. Add the okra. Reduce the heat. Simmer for 20 to 25 minutes or until of the desired consistency. Add the shrimp. Simmer for 5 to 7 minutes or until the shrimp turn pink. Discard the bay leaves. Spoon the gumbo over hot rice. Sprinkle with fresh tomatoes.