Travel Insurance

I am a Canadian Citizen and US non-resident alien living in Tennessee on an F-1 student visa. I have only been here since December and I still have Ontario Health Insurance coverage as I am a full time student. I also have supplemental health insurance through my university, however, it does not cover travel outside the US. I am going to south america for 3 weeks in May, and what I used to do was buy supplemental travel insurance through something like TD bank whenever I went traveling. However, now that I no longer live in Canada and I only have my OHIP because I'm studying in the US, I'm not sure what I'm elligible for? Do I buy supplemental insurance from a US insurer or from a Canadian insurer?

Well technically you're still a resident of Canada so you could do it the way you did it before.