I don't know why you did post a question into the "Your tips and tricks" section of the forum. A question about the Backup and retrieve FAQ needs to be posted into the Backup and retrieve section of the forum!
To find a Domain file it's best to use a freeware application called Find File
since Spotlight doesn't search everywhere. Once you downloaded and installed the application type ".sites" (without quotes) into the search field of Find File and it will list all the Domain files on your computer.
If you restored the whole system and the files are three months old to me it means that you restored from a three month old backup. Which means that all the newer stuff is gone.