Restoring an iPhone 4 to iOS 6.x via powermac G5 running OSX 10.5.8 and iTunes10.

My wife just updated her iPhone 4 from iOS 6.x to iOS 7.1. Now she has found that she can no longer communicate with her computer, a PPC G5 PowerMac running OSX 10.5.8, because the latest version of iTunes which will run on her platform, v.10, doesn’t recognize the phone. She’s used to synching contact and calendar information between the phone and the desktop computer, and that no longer works. I had thought that if the update turned out not to be what she wanted, she could just restore her phone to its previous state from the backup stored in iTunes, but now the phone says that it requires a more recent version of iTunes, 11.x, which can’t be used on her ancient computer.

Although my wife has an iCloud account, her computer pre-dates iCloud, and recognizes only the discontinued .Mac, so her phone has backed up only to her computer — and it seems that there is no way to restore her phone via the version of iTunes which will run on her PPC Mac.

She’s really bummed that the update has had this unintended consequence. Can she restore her phone and undo the update in some other way?

Thanks for any suggestions