Turbotax is not licensed for sale overseas, it says so right on the Amazon listing. I think this is due to national security restrictions on the built-in encryption technology used to transmit e-filed returns. So you really need to complain to the State Department.
You may be able to fool a retailer with a US address and US credit card, that's up to you. I would always recommend than an expat keep at least one US credit card and a US bank account (with a bank that has foreign branches, like BoA or HSBC) with a few dollars in it.
