You don't have to provide any alternate documents to the IRS proving your student loan interest deduction. If you are ever requested to do so, any documents that show that it was a student loan and any statements that show the amount paid and amount of interest paid will suffice. 

You can deduct student loan interest from a foreign country, as long as the loan meets the requirements of being a student loan (a qualified student loan is a loan you took out solely to pay qualified higher education expenses) and you have legal obligation to make the loan payments. 

The year-end statement is sufficient enough to claim the interest. When going through Turbo Tax interview, simply enter the name of your Lender and amount in box 1, as if the form is received.

All amounts must be entered in U.S. dollars on the U.S. tax return. You may use "government resources" or "external resources" in the below link for conversion:

https://www.irs.gov/Individuals/International-Taxpayers/Foreign-Currency-and-Currency-Exchange-Rates

Additional information:

https://www.irs.gov/Individuals/International-Taxpayers/Yearly-Average-Currency-Exchange-Rates