The easiest way is to copy the wiki folder into the wikis folder bob uses then in Control Panel -> Bob settings -> Manage Wikis -> Wiki Listing click on the 'update list' button. The wiki name will be the folder name, you can rename it under the 'Rename Wikis' tab.
If you don't want to move the node wiki than under the 'Create Wikis' tab next to Manage Wikis select 'a node wiki' from the list then enter a name for the wiki to be listed under and give the path to the node wiki then click 'Add Wiki'.