Apple has nothing to do with which printers are AirPrint compatible. Its up to the Manufacturer to add this feature to their printers. If they choose not to there is nothing Apple can do.
If the Printer is not AirPrint compatible, you can try looking for an App in Canon's Website.
http://www.usa.canon.com/cusa/office/products/software/mobile_solutions/canon_mo bile_printing_app_for_iphone_and_ipad
Or try a Print Server Application that runs on your computer and shares the printer out to devices on the network.
If you have a Mac Printopia is often suggested for that purpose. There should be similar alternatives for Windows PCs.