It's a beautiful quilt. While you don't have any twin beds, why not put it on a bed you do have, either as a topper with one underneath to cover the sides of the bed. Or under the bedspread and just use it.
If you don't want it ... ITA with the others, a donation back for another raffle would be a great offering. Even better, if you could give it back to the same group that it came from when you won it.
Good Luck!