You can call the hotel at +49 8161 966 0. That is probably your best bet to reserve the shuttle (9.75€).
You could also take the bus to Freising. According to
www.bahn.de it is an 18 minute ride and the bus departs every 20 minutes. I would just inquire at the information desk when you get there that you need to get a bus (2€) to the Freising Krankenhaus (Hospital). Are you aware that this hotel is about 35 km from Munich city center? Not that big a deal if you are mentally prepared, but a bit of a shock if you are not. Great train service so it is not that much of an issue.
For more info click
here.