You need to see where the crack is before getting worked up, if its at the top of the bore on the deck, then welding would be OK, deep in the bore is really wrong and a sleeve should be used. Boring one bigger would not kill the engine, its not ideal and will work, but a sleeve and boring to the original size would be better. Don't bore all bigger just to match one, sleeve one back down. In the future if something was to happen or it needed bored again, you will be out of material to cut and six sleeves will be needed.
Time to go see for yourself and push to get it done or moved, two months is way to long.
