For Hotels you might have a look at Hotel Uhland, which is not far from the main Hbf (10-15 min. easy walk). The Hotel is in a beautiful location, in a nice residential neighborhood.
With such a short time, you could consider a Munich Walking tour, explore Marienplatz, check out the Hofbrauhaus (as someone else mentioned, mostly filled with tourists - check out the unique "appliance" in the men's washroom), have a brief look at the Deutsches Museum or Englisher Gardens. You shouldn't have any trouble finding a way to spend the afternoon.
If you have money left over in your budget, you might consider a fine hot meal at the Sofitel Hotel, which is right next to the Hbf. The formal restaurant in the back has awesome food and service (but of course, it's not cheap).
Finally, you might stop by the EurAide office in Munich station to pick up your S-Bahn tickets for the airport run the following day. That way you won't waste any time on the day of travel. The EurAide staff speak English and are VERY helpful.