I found this when googling buy fruit trees.

Also noted this from an American grower about growing these trees - you need another apricot tree to get the best fruit:

Canadian White Blenheim

Taste test winner! One of the all-time top-scoring apricots in Dave Wilson Nursery blind taste tests. Syrupy sweet white flesh with firm texture. 500 to 700 hours. Partly self-fruitful: biggest crops if cross-pollenized by another apricot.

Well I've spent 20 minutes searching and every source I find is US. I gave it my all.

Here is a link that might be useful: Fruit Tree Nurseries in Ontario