Inside that same cavity (below the insert) you should find a plate with the model number, burner specifications and manufacturer.
Google the manuf./model and find the fan that will do what you want...or call one of the HVAC company's that installs products made by that manufacturer in Calgary and see what they have to say?
The fan dramatically increases the "utility" of a gas fireplace. Without one...it's little more than a "decorative" waste of natural gas. Well worth the price of admission...Git 'er done!
Cheers, Ron