Heat oil in 10-inch skillet over medium-high heat. If pork roast comes in netting or is tied, do not remove. Cook pork in oil about 10 minutes, turning occasionally, until brown on all sides.
Place pork in 3 1/2- to 6-quart slow cooker. Mix remaining ingredients except half-and-half and mustard in small bowl; pour over pork.
Cover and cook on Low heat setting 7 to 9 hours.
Remove pork from slow cooker; cover to keep warm. Skim fat from pork juices in cooker if desired. Stir half-and-half and mustard into juices. Increase heat setting to High. Cover and cook about 15 minutes or until slightly thickened. Remove netting or strings from pork. Serve sauce with pork.