One option would be to buy each herb seperately. The Black-Walnut is very effective against Tapeworm while the Wormwood more effective against roundworm. Read about the main 3 herbs above.
If I could not use the Black-Walnut I would substitue this for olive leaf powder.
Some of the more common killed by Olive Leaf are Amoebae, cryptosporidia, Giardia, pinworm, tapeworm, ringworm, and roundworm.
I think the olive leaf, Wormwood and cloves should do a fairly good job together. I buy mine in bulk from Mountain Rose because they are very cheap. If you want the capsules most healthfood stores will carry them.