Tortilla Soup

3 tablespoons vegetable oil
1/3 cup chopped onion
1 1/3 cups peeled, seeded chopped tomatoes
1 teaspoon garlic
4 cups rich chicken broth
2 teaspoons dried dill weed
2 chile peppers
4 soft corn tortillas
1/2 avocado, cubed
4 tablespoons sour cream
1/4 cup shredded Monterey jack cheese

Heat oil, then saut