If you don't mind a bit of touch up painting, take the bike apart, at least the headset, drill a small hole at the very end of the crack and then take it to a local welder and have him TIG weld it. Touch up paint it and you should be good to go. A small weld like that shouldn't cost hardly anyhing to have done.

Perhaps if it isn't covered by warranty you could ask the seller to split the cost with you to have it TIG'd?

Good luck, Jeff