Downtown you can find Reunion Island Coffee beans for sale at Luis Coffee Stop in Kensington Market.
The gentleman there once mixed me a "medium" blend of equal parts Privateer Dark Barlino beans and Las Hermosas beans. Rich and delicious with a heavenly aroma. When I lived abroad I'd get visiting friends and family from T.O. to bring me bags of this.
I think Le Gourmand (at Yonge & Eglinton or Bloor & Spadina) sells Reunion Island coffee. I'd recommend calling first.
The info for the Y & E location:
2177 Yonge St.
Sat.: 9am – 4pm
Closed on Sundays
Mon. - Sat.: 7am – 11pm
Sun.: 8am – 9pm
2177 Yonge St, Toronto, ON M4S, CA
Nearly 3.5 years after you posted your query, I'm happy to tell you that I contacted Reunion Island Coffee with this same question a few weeks ago and learned that my closest retailer in uptown Toronto is:
FLAKY TART INC
711 MOUNT PLEASANT
TORONTO, ONTARIO, M4S 2N4
There's also this Canadian online retailer: http://culturedcoffeebean.com