This is unfortunate that you are leaving us, but at the end of the day, it's your personal choice. The first step is to apply through the OUAC:
http://www.ouac.on.ca/ouac-105/
I think you have to use OUAC 105D...then i think it would be a good idea to get in contact with ryerson, see what they want..maybe they want some documents form you and such, so it would a good idea to get in touch with them after you apply.
Mac is a great school, but as i said earlier it's your choice at the end of the day. Good luck with everything!