Bricks, Masonry, Asphalt and Concrete - How to build up concrete garage transition

I have a detatched 2 stall garage. It used to be an old carriage house, and the transition between the driveway and the slab of the garage has become very uneven over the years. Although it is only an issue with one door, when the door is closed, there is still a 1-2 inch gap from the center towards one side of the door. What i am hoping to do is to somehow "patch" the low part of the transtion and bring it up to where it can seal against the door properly. Can this be done? I suppose another option could be to make the high side lower if that would be easier, but it seems like it would be harder to take a measured amount off cleanly than to add.

hmmm...hopefully the lack of responses are result from a poor description. I didn't think it would be that difficult for the pros here. Please tell me there's a way to do this!:thinker: