Not much input here, but that is one of the risks of buying overseas. They will warranty the frame but you have to cover shipping costs. If you do ship it back, make sure you have a price on the return shipping, because you will probably have to pay that also. Return shipping will not be as $$$ as sending it to Waltly, but calculate that in your costs.
I have to look at my Waltly, because I hear creaking from the seat-tube area, and your frame is the second in as many months that I have seen with a crack in that area.
Best of luck!