BLEEDING A CLUTCH

My 94 Hilux Surf (same as 4Runner) has no resistance on the clutch pedal after running dry of clutch fluid.
Can someone tell me whether this is an expensive job or is there a simple way of bleeding the system much like brakes are done.
The pedal clunks down and has to be lifted by hand so driving it into the workshop is going to be a drag anyway.
I suspect a leak in the system as it has needed fluid topping up every few hundred miles.

Any ideas will be appreciated . Thanks
Martin