Most of their stuff is either office-lady-ish or just generic cute Taiwanese style, but they have some cutsews that I think would look nice under a JSK, like this and this or this. Also some blouses, like this.
I have some clothes by them that I bought when I was in Taiwan, and the quality is pretty good.
I'm planning on ordering from them soon (once I figure out what else to order to get up to their international minimum of 15 pieces, and if I do I'll let you all know how it goes :)
Their main page is here but it's a bit crash-prone and the stock isn't always accurate. They have international ordering instructions here. You have to create an account with them (even though international orders are by email) - instructions on how to do that can be found here.
You can estimate shipping using the Taiwan Post page (should work okay with Google translate).
Apparently YesStyle carries their stuff, but it's at some ridiculous markup. I can't find this turtleneck in the TF store right now, but similar styles are about 350 NT or less (~$12).