You may have to get it online. Try ebay. In Australia there are many websites but not too sure about US.
I've never used it, but heard great things about it for chronic illnesses.
Don't know if you have a Henry's Market in your area, but I was there the other day picking up xylitol, probiotics, and colloidal silver.
Saw the cat's claw, they have a few choices from about $6-15.