What Andy said, except you measure the distance by selecting an appropriate set of vertices that you want to centre on the origin. Then you read those coordinates into the 'move to' boxes (tap the > button next to them). Note these down on, say, a spreadsheet. Then select the whole piece you want to move, and get the coordinates the same way. Note them down in the same spot as well. Then comes the whole of the magic: Subtract the former numbers from the latter.
This set of coordinates is what you want to move the whole object to, to get it into the right position. And that's the whole cake.
