Delete Libraries after creating Vault

Vaults are for added safety, a backup in addition to the libraries. Why do you want to delete the libraries? Do you not need to browse and edit your images any more? If you only want one item - library or vault, it would be much more useful to keep the library.

I would suggest exporting your 2012 pictures as a new library, and then deleting them from a main library.

Or, better yet, just create a new library and use that for 2013.

A vault is not intended to be an archive.