All you need is a bolt extractor and some lubricant. A 30 second Google search found
this, which is Mastercraft and, as far as I know, should come with one of those nifty lifetime warranties.
Spray some lubricant around the outside of the bolt, let it sit for a bit, then go to work with the bolt extractor. You ought to be able to pop it right out. Do make sure you have a replacement on hand and do get to this sooner rather than later -- driving around with only three lug bolts is not recommended, to say the least.
Cutting your rim apart is also not recommended.
If you haven't already done this, one thing that I also recommend for Canadian drivers is to get your winter tires mounted on an extra set of cheap steel rims. This allows you to keep your nicer rims (whether OEM or aftermarket) out of the slush and salt and other crap on Canadian roads in the winter, and also allows you to change your tires at home. With a bit of practice, you ought to be able to do the whole set in 15 minutes or so.
Just remember to take them in to get balanced periodically, and you're good.