HT4137 Problem setting u an iPhone 5 with iCloud backup

Can anyone assist. I have bought an iPhone 5 and don't have my lapto wi me. I have backed up my iPhone 4 using ICloud but when I try to set up the iPhone 5 with restore from iCloud backup it says the backup was done n a new IOS version than the iPhone 5. Without my laptop I can't use iTunes to update the new iPhone IOS and yet I also can't get passed set up unless I set it up as a new phone????????

any ideas.  Is it possible fr the apple store to update the new iPhone 5 IOS first for me???