The only way would be via the Finder app built into the phone but if the phone is turned off, its useless. There is no other options sadly:(. If someone turned it off or took out the sim card, they can just insert their own & use it thus you are not able to find it. So sadly there is no way:(
You can however report it stolen / lost with Rogers & see if they can offer you a a iPhone 4S or another phone for a price. ( Prices vary).