I was looking at this as well. I used to have a Garmin V and I used Mapsource Atlantic V4, I up graded to a 2610 with Atlantic Version 7 mapsource. Unfortunately V7 cuts Iceland in half so you only get the eastern half. I have not checked but I suspect the western half is on the Americas Version. Version 4 Atlantic has even less of Iceland. I also have Mapsource World map which has Iceland but not in great detail and Worldmap does not have Auto Routing.
If you want to try Worldmap you should be able to find a copy on ebay.