iTunes star ratings, play count, playlist info

Your question is very unclear. If you actually moved the iTunes library folder to the new drive, then you would have kept all the info the library file contained. It sounds like you moved your music files to the new hard drive, but then started a new iTunes library file. If that's what you did, then you may have lost all the previous information. The iTunes library folder has a default location in the MacIntosh HD/user/(your name)/music/iTunes folder. It's possible that a copy of the older library file has been kept.

The iTunes library file keeps track of where the music files are located, so when copying your music files you would have to maintain the same drive heirarchy in the new location in order to make use of the old library file. Assuming that's the case all you have to do is copy the old library file to the location I mentioned above. You will lose whatever changes you've made in the interim.