Most scanners will name files sequentially, so you do not need to drop them or rename them.
Once you have the scans in a folder, you can set up a Panorama form that will display the scan, and from that, the data can be typed into appropriate fields. In fact, that form will allow one to see the scan along with the typed in data, so you would be preserving your original card catalog within the computerized catalog, which would be a nice touch.
By the time you get this all done, the server version will probably be available, and you could use it to serve web pages, as noted above. This is the best way to maintain a card catalog: Anyone with an internet connection can access it anywhere, so they can see where an item is (or is supposed to be), whether it is in or not, reserve it, renew it, etc., before coming to the library. I do that with libraries whenever I am looking for something specific.
One thing, though, there is probably library catalog software available commercially, and you should look at them to decide whether that would be a better option. Even so, you need to enter the card catalog, and Panorama should work for that.