Yes you will need to take it to an instrument shop. The cost will vary depending on whether it is mechanical or electronic. I had the speedo recallibrated and the odometer fixed in my Cordia recently. If it's a mechanical speedo (cable driven) you have two options 1) the speedo needle can be repositioned
2) fitting a ratio box to the cable
If you fit a ratio box the odometer will read correctly as well. To work out what ratio to use or how huch to adjust the needle, the shop has to determine how many revolution the cable is doing at a certain speed or count the number a revolutions over given distance.
This sort of work is not cheap unless you have a mate working in an instrument shop