If you are still looking for a place to stay you could always try the Botel on the canal next to Central station.
When we have stayed in Amsterdam (4 to 5 times a year) we have been fortunate to find a 5star hotel at the price of a 2 to 3 star, usually booked about a week before we go, unfortunately being a large party they probably won't discount that many rooms!
The best area for choice and variety to eat is in the Leidseplein area
Hope this helps
Not sure if you have found a hotel yet but a good reliable site is
have used them often
hope this helps!