Can anyone recommend accommodations in Garmisch for a 3 night stay?
Just remember this is passion play year, so make your reservations early.
Try the Fraundorfer. Techinically, its is Partenkirchen, but that's splitting hairs.
http://www.gasthof-fraundorfer.de/
The Passion Play probably only has a minor effect on room availability in GaP. Consider that the play performs 5 times a week for 5 months, and seats about 4,500. During the holiday ski season, GaP has enough room capacity for about 20,000 tourists at any given time. Rooms won't be that tight.
This is about 3km from Garmisch in Farchant, but it's a great place to stay. It's a nice little village with an awesome cafe within walking distance of the gasthaus.