svnadmin restore question

[Maureen Barger]

Hello - in creating an iteration in Subversion 1.5.1 I inadvertently
deleted the source after I created the new iteration. I was able to rename
the new iteration to the old, but in the process lost the branches
directory. I have a backup from a point in time before the iteration was
deleted but am unsure how to restore the branches directory only.
Can anyone provide guidance?
Thanks.