In 1-quart saucepan heat 1 teaspoon oil; add onion and garlic and saute until onion is softened.
Add green pepper and saute for 3 minutes longer.
Add tomatoes, wine, and olives; cover and let simmer, stirring occasionally, for 10 minutes.
Sprinkle both sides of cod fillets with salt and pepper.
In 9-inch skillet heat remaining 2 teaspoons oil; add fish and cook for 3 to 4 minutes.
Turn fish over and top with vegetable mixture; let simmer until fish flakes easily when tested with a fork and vegetables are hot, about 3 minutes.
Transfer to platter and serve.