Apparently you did not search very well. On booking.com 126 hotels in the very centre have rooms available for your dates, in every price category.
Even the NH Amsterdam Centre has standard doubles, superior doubles and suites available.
All you have to do is take the trouble to go to booking.com and book!

Sorry ... just read about a 2 day extension (I thought you needed a room for just one night, the 23rd). Saturday 24th seems indeed pretty problematic in Amsterdam.

Check in the Netherlands forum at TripAdvisor... there are a lot of Amsterdam residents there who may be able to make more suggestions...

MyriamC..I would not have posted unless I initially looked.

Haarlam is a nice place with a fantastic railway station (if you like that sort of thing)