Hey Reddit, I need some help. How can I download games I want to purchase from Amazon if I'm temporarily out of the US for a while?

I want to buy Red Alert 3 on Amazon for $10 (it's $10 cheaper than everywhere else I've found) and download it directly onto my laptop, but I'm currently out of the country for about a month. What can I do to download it from Canada? Are there any instructions I can follow on the web? I really appreciate your input. I am sort of a tech-impaired duck. Thanks!

This is what I'm stuck on ): http://puu.sh/bOQ8