If it's anything like the Ford's hydraulic setup....replace it while you have the chance. If it's low, then there is a leak in the system somewhere and it's just going to happen again. With the system being low, it's not releasing the clutch properly and thus causing the blocker rings and synchro's in the transmission to wear faster than necessary. On the Ford's there is a way to bleed them, although with the design of the master cylinder and the way it's mounted, you would ideally need to pick up the front end of the truck off the ground about 3-4' in order to get all the air out of the system. This is why the Ford's were notorious for bad clutches... I'm not sure about the style of the jeeps though....
Mine is doing this right now, and I've got parts coming in this week. New clutch, master & slave cylinders, and I'm still trying to find a flywheel, but I may just buy a new one to make it easy....
*EDIT* I believe this is what the slave cylinder looks like if I found the right part. It looks like you are able to bleed the clutch, although I still recommend that it be replaced because of the leak.