In a large pot of boiling water, cook fettuccine until tender. Drain.
Mix alfredo sauce according to package directions (with milk and margarine) in medium saucepan over low heat. Cook until thickened. Stir in garlic powder, basil and oregano.
Steam broccoli in microwave according to package directions.
In pasta pot, combine broccoli, pepper, tuna and fettuccine. Pour sauce over pasta mixture and toss.