Preheat oven to 400°.
Trim fat from roast; set aside.
To prepare fruit stuffing, combine 1 cup Marsala, apricots, and prunes in a saucepan; bring to a boil. Reduce heat to medium; cook 5 minutes. Melt margarine in a nonstick skillet over medium-high heat. Add onion, celery, and garlic; saute 2 minutes. Remove from heat; stir in apricot mixture, breadcrumbs, and next 5 ingredients (breadcrumbs through pepper). Cut a 1 1/2-inch-wide horizontal slit into the short end of roast; cut through to the other end of roast to form a deep pocket using a long thin knife. Spoon fruit stuffing into pocket; pack using the handle of a wooden spoon.
To prepare spice rub, combine sugar, 2 tablespoons Marsala, and allspice. Score a diamond pattern on top of roast using a sharp knife; spread spice rub over top. Place roast, rub side up, on a broiler pan coated with cooking spray. Insert meat thermometer into meaty part of roast. Bake at 400° for 1 hour and 15 minutes or until thermometer registers 160° (slightly pink). Cover and let stand 10 minutes before slicing.