normally a abs wheel speed sensor will just bring up the abs light.the speedometer going out normally means a fault in the module itself as fiestas with abs use wheel speed for speedo and not a sensor in the gearbox.best bet is to have a diagnostic test done at a dealers to clarify as abs modules are pretty pricey.

ps if it turns out to be a module and is just out of warranty you could try calling ford customer relations to see if they will contribute towards the repair