Fruit Crumb Cake

1 1/2 C Self-rising flour
2 C Quick oats
1 1/2 C Brown sugar
3/4 C Margarine
1 (21 oz.) Can pie filling

Mix everything together, except the pie filling. Reserve 1 cup of crumb mixture for topping.  Pat into a 9x13x2-inch casserole dish that has been sprayed with a non-fat cooking spray.  Pour one can of pie filling on top of crumb mixture.  Sprinkle with rest of crumb mixture on top of pie filling.  Bake 45 minutes to 1 hr. at 300 degrees.