From conductivity measurements you can not find out mobility if you do not know carrier concentration. But if you are able to go to high field region where space charge limited currents could be measured then you can find the mobility from the same experimental set up. But, you can observe space charge limited currents only when thermally generated charge carriers are much smaller than charges injected from electrodes, I.e, your sample should be fairly resistive. You can go through the famous book " Current Injection in Solids" by Lampert and Mark for the equation used in case of SCLC. Mobility of charge carriers can also be obtainedobtained independently by time of flight experiment.