Savory Swiss Steak

Yield:	6 Servings
Categories:	Main Dishes, Slow Cooker, Steak

1 1/2	lb	Round steak
1/4	c	Flour
2	ts	Dry mustard
1	ts	Salt
1/4	ts	Pepper
2	tb	Butter
2	tb	Oil
1		Onion, finely chopped
2		Carrots, peeled and grated
2		Stalks celery,finely chopped
1	cn	(16 oz) tomatoes
2	tb	Worcestershire sauce
1	tb	Brown sugar