Cajun Shrimp-and-Crab Sauce

~Ingredients 1 pound unpeeled, medium-size fresh shrimp 1/2 (16-ounce) package andouille sausage 1 medium onion, chopped (about 1 cup) 1 green bell pepper, chopped (about 1 cup) 1 tablespoon olive oil 2 garlic cloves, minced 1 tablespoon all-purpose flour 1 3/4 cups chicken broth 1/2 pound fresh lump crabmeat, drained and picked 1/2 teaspoon Old…