Let me know if you have any luck with drugstore4save, or find any other supplier for niclosamide. I never could get the drugstore4save site to accept my credit card, and my UK-based credit card company cancelled and reissued my card for security reasons after trying to use them. No idea if they are legit or not.
You could try just a big praziquantel dose instead. I don't think the niclosamide is totally necessary for Tapeworms and I think may be just used for beef Tapeworm so that you can see the scolex being expelled in your stool and so know when it is treated (praziquantel vaporizes the worm so you won't expel it in stool, whereas niclosamide kills it without causing it to disintegrate).
I have had some luck with Praziquantel that I got from eBay for what I believe is schistosomiasis. They have the 600mg tabs advertised as for animals/fish but these are identical to the human tabs. I can PM you a link.