The price for an IO-540 is very good but it is very unusual for overhaul shops in the USA to pick up the shipping costs I guess that I could add this shop to the very small list of overhaul shops that I would use in the USA.
The problem that you have is the time that it has taken to get the aircraft sorted and flying the engine across the Atlantic twice can't of helped with the downtime.
Some one above did hint that the engine was for a Robin hence the O-360 comment.