I used Mrs Chang´s herbs and they are fantastic. I used GCG which crunches and softens Gallstones and I also took Chinese bitters and I got on well with both.
I stopped using her herbs because I live in Brazil and I pay too much freight to get her hebs here. So I started using Chanca piedra Tincture which is a native plant from Brazil and easy and cheap to get. For your information I pay 4 Dollars for a 250 ml bottle here.
Chanca Piedra is great and you feel good after a few days taking it as it really dissolves the stones. And as Luz said it also works for kidney stones.
I wish I could help you with stores, but all I can say is that the effects of Chanca Piedra are wonderful.