How to connect iDevice to fresh install of iTunes without losing content on iDevice after computer HD failure.

I sync my families iDevices to the same iTunes account and have lots of media and playlists both burned/imported from CD collection as well as purchased from iTunes. Computer hard drive failed causing the purchase of a new computer without the chance to backup iTunes library.

How do I connect iDevices to new iTunes account without it wiping the iDevices content away. I guess I want to transfer content from iDevice to new iTunes. Is this allowable and if so can I be directed to article or advice on how to proceed? Thanks.