iTunes does not recognize folder structure when importing music
Doug's AppleScripts for iTunes are a good place to start looking for any iTunes scripting solutions.
In your case Tags Mirror Artist-Album-Filename looks very promising:

This script copies the names of the Artist folder, Album folder and filename (minus its extension) of the selected tracks' file paths to each corresponding track's artist, album and song name tags, respectively.
For best results your files and folders should be arranged in this format:
Artist folder / Album folder / filename.xxx