Here's a download link for the FileMaker 11 30 day trial: http://info.filemaker.com/Us_en_FileMaker_Pro_11_Trial.html
You can download and install the 30 day trial. Then:
Launch FileMaker 11.
Choose "new from starter solution"
Select the lending library template and create the .fp7 file.
Quit FileMaker 11
Launch FileMaker 12 and use Open from the file menu to select and open the .fp7 file that you just created. This creates a new .fmp12 version of the file that you can open and test in FileMaker 12 to see if it works for you.