Just copy the eagle.key file from your previous installation to the new one (it should be in the 'bin' subdirectory).
As for transferring libraries: DON'T! Don't modify Eagle's libraries directly -- create your own and copy their parts into your own for modification. If you know which ones you modified you can just copy the .LBR files from the old installation to the new one....but this is not a good long-term strategy as you will overwrite library fixes and updates in newer versions.
The Aussie Shield
: breakout all 28 pins to quick-connect terminals