The Hotel Chariot offers a shuttle bus service to/from the hotel. Time - depends on the traffic and whether rush hour or not - from memory @ 45 minutes max.Yes you can get a taxi but on the two visits there, I only used taxis around the area: hired a car on first visit and second used taxis.
Amsterdam Central is best via train at the station as it's a short trip there but I'm sure a taxi would be relatively inexpensive. Get the hotel to call for one and also get them to give you a ballpark price. The drivers all speak English and are extremely helpful. Enjoy your trip!