I looked around a bit and I see Banana Hobby( yet another company to proceed with caution) sells it too but doesn't show a wing set.

Here is the manufactures web site showing a parts list:
www.art-tech.com/english/ArticleShow.asp

Here is a place that shows stock:
hobbyfly.de/en/rc-airplanes-1/aircraft-spareparts-209/art-tech-parts-299/art-tech-diamond-2500-spare-part-252/

another that shows coming soon:
www.wowrcmodel.com/spare-parts/art-tech-spare-parts/diamond-2500-spare-parts/5u021-main-wing-set.html



How bad is the wing damaged? Depending on the foam type these things can go back together and be made as strong or stronger than when new. Take some pics and post them. We may be able to help you repair it !