One thing you can do is to pay $90 (per pax, per direction) and buy preferred seating (e.g. exit rows) for your flights. Would work out to $360 for the round trip, assuming they are available. Not business class, but at least you get some leg room.

You might be able to do this from the aircanada.com 'Manage My Bookings' page with your AC locator number (this is not the same as your Orbitz confirmation #). If not, call AC directly and have them process it. The booking still belongs to Orbitz until it gets transferred to the airport, but I've never had issues with preferred seats by calling them directly.

Also, if you do a paid last minute upgrade (LMU) to business during check-in, then the preferred seat fees get refundable (you may need to call in for this as it doesn't always happen automatically).