Between the two aforementioned books you have everything covered. The Howard guide is available in the UK, but we got the only copy from Needlesports at the time. Klatring i Romsdal is hard to find (in my experience) anywhere but Romsdal where the bookshop and quite a few campsites have big stacks of it.
Romsdal is a much better place to be than Alesund. I added a few of the crags around Alesund to the database on here, and the website for around there is:
http://www.klatreklubben.no/uteklatring.php If you really want, or the weather forces you, to go do some sport then it's an ok place to be. Personally I'd go hiking instead though. Make sure you research the DNT and their fantastic hut system. ut.no / norgeskart.no for maps (they're at least OS quality), yr.no for weather.
I had to turn away from Romsdalhornet due to the heavy snow in July (it was a funny year last year), if we'd had axes it would have made an amazing day out! It looks like an amazing day out, should be a great view of Troll Wall from the top too.
Nesaklsa Cliff, Right-Hand Buttress (5) - can't recommend this, but my partner took a deviant route up the first pitch on some barely stationary bits of flake. It is close to town and has a dead easy walk off down a massive stone staircase though, that and the near perpetual daylight were handy with a 2300 finish.
Norafjell, Nedre Del (6?) - this was a spectacular day out! Can highly recommend anything on this crag, had big abseil bolts in place to get down on too.
Be aware that the area isn't very busy, so don't expect to see well worn paths, signs of use, even any other people!
Other wet weather activities are driving over Trollsteigen (worth it in itself) to go rafting in Valldal and eat strawberries, or carry on further down to get a boat through Geiranger. Google image search will tell you why.
If you're flying into/out of Alesund then there is a little bouldering to the North (Roald) or a sport crag with an amazing roof (Valderoy) to the south which you have to drive past to get to the airport.
Don't forget to stock up on duty free, booze is steeply priced!
If you want any more, drop me a message.