The DB8 is a great lost distance antenna. As a result, the beam width is restricted. I would suspect that you cannot get both Toronto and Buffalo with a fixed setting. I would start with the DB8, and then check the pre-amp. If you need one, then it should be a good one. Using those together you can then check whether you need a rotator.

But along the way, you should replace ALL the coax on the mast with new, and check whether the rotator is actually dead, or just resting since the wire died!