Toyota Repair Problems? Ask a Mechanic for Answers ASAP
The speedometer can be purchased at the toyota dealer, there may be aftermarket units available from other sources so check around on the internet, most states in the US require that the replacement speedo be set to the original odometer reading, some states require a label to be attached to the door stating that the speedo was replaced and stating the original mileage, if you buy it from the dealer they will include setting the odometer in the price, if you buy it used or aftermarket then you will have to take it to a certified speedo repair place to have the correct odometer reading put in. In most states it is against the law to alter the odometer reading.
I don't have step by step instructions for installing it but if you are handy with this sort of thing it's not that hard, just remove the instrument cluster and the disassemble the back of the cluster to put the new speedo in, if you don't feel comfortable tackling this then a speedo shop or the dealer will do it for around $90.