Like Dave has said, it aint the worst job in the world. A good mechanic would fix it in a couple of hours or so.
It's deffo gonna be the clutch oil seal in the transfer case IMHO.
If it is the oil seal:
It means supporting the engine from underneath, releasing the lower engine mount, pulling the clutch cover off, flywheel and clutch assembly off then replacing the seal. You also need to replace the clutch plate if you have lost drive due to it being covered in oil. I've tried shortcuts and using old oil soaked clutches that have been cleaned in all sorts of chemicals, but they never work properly.
Tools needed for the job:
Spanners,
Sockets and breaker bars/ratchets,
Hammer!!!!
jack and stand to support engine,
flywheel puller,
elbow grease
PS: to undo the bolt in the centre of the flywheel you'll need to lock it in place. To do this there is a special locking tool that fits through the starter motor hole, but 99% of the time, people use a large flat bladed screwdriver or pry bar through the hole on the ring gear.
Two days shouldn't be a problem at all, as long as you strip it today to properly diagnose it and get the parts sorted ASAP.