Because of the front seal leak I would suggest that the solution should be a rebuild. Chances are that you have an internal leak or as noted a low output front pump. Since it is necessary to remove the tranny to reseal the leak and because it undoubtably is rather old, all the seals should be redone. Its only about twice the labor to do the whole job compared to a proper front pump reseal.
You might want to do a service on it as the only other thing you could have is a plugged filter. By removing the pan you also can view whats in the bottom of it. If there is any clutch material steel or brass the thing should be rebuilt before the significant failure comes.
Bosch Master, ASE Master, L1
33 years MB technician