Weaned on the bad old days of the 1980's when if you parked your car in Amsterdam with foreign plates you could pretty much expect to be broken in to, I prefer the safety of the Transferium at the Arena in Bijlmer. As you can see from the link, the max is 14.50 per day and if you want to really save and don't mind the hassle to and fro, you can get it down to 5.50 a day just by making sure you go and get your car, exit the garage and go back in, within a 24 hour period. There are other places but they are not enlcosed, except for Europarking, but you pay more there as it is in town.
Your ticket includes two round trip metro tickets into town. Make sure that you stamp the ticket both ways, especially on the way back from the centrum.
http://www.amsterdamarena.nl/