I agree with the majority that it's yours to do with as you please. The guild members who judge you negatively are probably already upset they didn't win the quilt, it falls into you can't please everyone catagory!
In the end do what you and your husband deem 'right' for you don't pay a wit of attention to remarks by any busy bodies. In these economic times and being retired that $600 (if that is what it will sell for) for you might make a real positive impact on finances for you and DH....lf that isn't an issue then donation might be YOUR choice. After all is said and done it's YOUR decision as it was won far and square.