I think you can do it from Windows...haven't tried it but it should work... Copy the files using Windows Explorer (not to be confused with Internet Explorer). You can get there by clicking on My Computer or pressing WINDOWS_KEY+E. If you have your Canon connected, it should show up as a device (look in the left pane to see if you see it). See if you can copy files to that camera device (using copy&paste, drag&drop, etc)...
You should re-format the card (using the camera) after you do this. Some cameras get confused if you put your own files on the memory card.