not an officially released CD so you'll have to go to various places to download most of the tracks.
Goodbye Yellow Brick Road and The Sun Ain't Gonna Shine Anymore were
done for Warchild, and you might be able to get them
from Warchild's website. Other than that, the official Keane shop may still have a few of the songs: The Happy Soldier is on the "Sunshine Retrospective" EP; Walnut Tree and Snowed Under are on the "Somewhere Only We Know" single. I don't know what country you are in, but the US itunes has The Way You Want It, Snowed Under, and Walnut Tree. Other than that, you could try amazon and other legal download sites; 7digital usually has a fair amount of Keane songs to download too.