If you can get a belt to omit the p/s pump you can save the pump from any additional wear, but I would think the pump should be replaced due to wear from running dry earlier. Any fluid you add now will just get on the road from your leaking box anyway. If there is some way to just plumb the pump lines together so fluid just flows from and then back to pump would be ideal, but not really worth the headache. At this point running the box without fluid for a short drive should do no additional damage.
Unless you are talking a small leak that takes a mile or more to empty out the reservoir, then I'd just keep the tank topped off every time it would leak down to a half full reservoir. The tow is best, especially if you have 10+ miles to get to your mechanic.