Hi ! I have the same problem and was very very anoying for me because I was in the Apple Store from Geneva to change my iPhone 4S for an other reason (head phone static issue) and they changed it. The backup with iCloud was ok (I don't know why it worked there and not at home).
But the problem was: How can I restor my iCloud backup without any Wifi???
You can share your mac connection ! And it works great!
So I habe an iMac connected with Ethernet. I go to System preferences > Shared > Internet Sharing (mine is in french so I don't know the correct word in english ! ) and activate it ! On the right box, activate Wi-Fi and go to Options Wi-Fi. Here choose the name of your new Wi-Fi connection and here you are !!
Connect your iPhone to the new Wi-Fi network and enjoy !