I found this, unfortunately it is in Danish. But if you divide the figures by ten, you'd have the approximate price in pounds, VAT included, and are one-way.
Envejspriser til Island 2011
If you scroll down, brining your motorcycle and just one adult is just around £225 for the high season, £165 for the shoulder seasons, and £110 for out-of-season.
Without a vehicle, you're looking at £75, £55, and £40, respectively.
There's a £12 fee ("Tourist Tax") for leaving the Faroe Islands.
A guide for the different season is:
High season (Blue) : 18.06-26.08
Shoulder seasons (Orange) : 14.05-17.06 / 20.08-29.09
Out of season (Green): 09.01-12.05 / 17.09-22.10
You can check here when and where (there are exceptions to the dates of the above:
Smyril Line - Sejlplan 2011 - Danmark, Færøerne og Island
I can translate some more if you want me to, but this is a start, I hope
EDIT: Sheesh, I missed the Subaru part ...
For those prices, click the top link and look at the top left box. Cabin prices are the top right box.