How do I add media files to iTunes when my iTunes library file is out of date?

My 2007 iMac died. My last backup was done 7 months ago. My iTunes media folder resides on an external drive, so all of my iTunes media files are unaffected, but when I set up my new 2012 Mac Mini using my last backup, my iTunes library file will be 7 months behind. In the past 7 months, I have added around 2,000 new media files to iTunes. So my question is this: what is the best way to add those 2,000 files into iTunes? Is it as simple as drag-and-drop? They are already in the iTunes media folder, I just need to tell iTunes they exist. Thanks for any help!