Parking for the Eatons underground shopping complex is street parking by meters that have to be rebooted with money every 2 to 3 hours..
Not sure whats at that St Urbain street address but if its just general street parking you may have to circle the block a bit to find a legal parking spot..
Be careful not to park in restricted zones that are for local residents only,the sign for that would be a red square with a parking zone/sector number on the sign like the ones in these signs
You might be better off just paying for an indoor parking spot for your entire stay as you're car will just be a burden the whole time you are in the city..