Looking for a 2 bedroom flat in the Museum area of Amsterdam, for a week.. suggestions?

I'll be joining a friend to explore the museums of Amsterdam again next April. I've been to Amsterdam before, but not stayed in town too often. This time I want to be near the Museumplein and I need a 2 bedroom flat, near trams (or, ideally, trains). Mobility issues mean that I need to find someplace that does not have steep stairs, or has an elevator. Do you have any suggestions for me? Many thanks!