Hmmm, this is where things get tricky...
Most pre-built desktops (eg. HP's, Dell's etc.) aren't really built for decent gaming (which I assume is what you want if you're spending $1500) and the ones that are aimed at gamers are very expensive (eg. Alienware, which have a starting price of 2000 CAD).
This one from HP is fairly decent:
HP Pavilion HPE h8-1121You'll need to get a screen/keyboard etc. with that as well, but at $999 you'll be well within budget.
It's a bit tricky for me as I'm not Canadian (obviously) so I don't know what websites over there are reliable other than the big box retailers (eg. Dell, HP, Newegg) so I can't really hunt out the best deals from boutique retailers as I don't want to direct you to a site that isn't trustworthy or whatever.