Sorry about saying Event Manager X "importing", it is actually a tool to help FCPX by managing the import into Libraries as you choose. There is a link to the application in the article, just under "Smarter Upgrading". It is free, and automates some of the steps that would make for the best updating process, especially if you want more than one Library.
If you responded to the 10.1 updating process with a "save" when it asked you what to do with the stuff it updated, the old events and project folders will reside in a folder called "'harddrive name' Old Final Cut Projects and Events", in the same folder they came from. If you asked FCPX to trash them, they are in your trash unless you emptied your trash since you moved them there, and that would mean they are now deleted.
If you trashed them, you would be best to get them from your backup.
The import/ update into 10.1 is where you separate the Events.
Personally I love that all the files are in the singular bundle of a Library. My workflows are seldom connected to each other, and I've used tricks (disc images) to get them segregated from other "projects" in the past.
warm regards.