The museum is located in the beautiful baroque Kulmer palace (1776, a national heritage) in the Upper Town – a historical part of Zagreb, full of museums and tourist attractions. It's a little hard to find the entrance to the museum, I actually circled the building twice in confusion. The entrance looks like you're entering the restaurant (see below).
The entrance fee to the museum was 30 Kuna (approx. £3) - and the exhibition had free Wifi which was also useful for planning my way to my next destination. The museums cafe is pretty good value for a snack - I had a coke and a small meat pastry and that came to 30 Kuna.
This museum is definitely worth a visit - the exhibition is relatively small, so you'll have looked around within an hour and can head off to a number of other museums just moments away.