Update can be obtained from the redelivery terminal at the in world store
http://maps.secondlife.com/secondlife/Fashion%20Boulevard%20II/132/176/22
Unpack the package into your inventory, then detach your old HUD and attach the new HUD. If you have links remember to replace Links.
If you have your HUD LOCKED you will need to UNLOCK it to detach it, then LOCK it again once you Attach the new HUD.
If you also use the Rulebook Addon, this will need to be reinstalled into the HUD by wearing the Rulebook Installer. (Make sure have you the latest version of Rulebook, its always best to also obtain a redelivery of rulebook at the same time as the Wardrobe HUD).