No need to despair... Clutches are not all that hard, and you do NOT need a transmission jack or air tools to do the job -- hand tools and a friend will suffice...
Also, you can easily change out your rear main seal once the flywheel is off.
I doubt that the oil from the rear main destroyed the clutch. I've changed tons of clutches in my day, and I've yet to see one soaked in oil from a leaky rear main seal. The seal is on the opposite side of the flywheel, and any oil that leaks is thrown off and drips out the bottom of the bell housing from the centrifical force on the spinning flywheel. It never hits the clutch.
Your problem is more likely from plain old wear. I'm not sure how many miles you have, but any time after 70 K, it is due for a clutch most of the time. Also, a lot of guys have the habit of resting their left foot on the clutch pedal, which will tear out a clutch in half the time otherwise needed. I've especially seen this in off-road driving. Just keep that foot planted on the floor and trust the truck -- or get an auto...
Your problem with the clutch pedal is due to the hydraulic throw-out bearing -- not the actual clutch itself. Yours sounds like it is sticky or frozen up. It will need to be replaced when you do the job.
Steps to changing the clutch (briefly):
1. Remove the negative battery cable (you'll have to pull the starter)
2. Remove the driveshafts
3. Remove the transfer case linkage, shifter, wires, and vent lines
4. Remove the t-case -- it has 5 13mm bolts and it will slide off the output shaft of the transmission once you get all the bolts out. It will not drop straight down.
5. Remove the crossmember and the mount from the bottom of the transmission
6. Remove the starter and the front block-off plate bolts
7. Remove the bell housing bolts -- do this with a long extension and an impact swivel (or an impact swivel socket -- use the impact variety, as they don't "float" around as badly as the chrome universal ones do -- tape it with black tape to hold it stiffer if need be)
8. Disconnect the hydraulic slave cylinder from its fitting in the side of the bell housing -- this takes a special tool that costs about $5.00. It is a pop-out type of hydraulic fitting -- press the tool against the inner ring and the hose will pop out. It has a check valve so you don't loose all the oil, or have to bleed the clutch slave cylinder.
9. Slide the transmission to the rear and lift it out of the way. Do this "bench press" style -- it is not that big a deal.
10. Remove the pressure plate and clutch disk by taking out the bolts around the outside edge of the flywheel. It is under spring load, but it will not "fly" off. Loosen the bolts around the flywheel a bit, then loosen them some more until they are all out. You relieve the pressure that way. Taking out all the bolts on one side will warp the pressure plate (not critcal for the old one, but important for the new!)
11. Loosen the flywheel bolts (don't worry, the flywheel will only line up ONE way -- the bolts are spaced weird so this is the case) and pull the flywheel. Take it to your local auto parts store and have it refinished.
12. CAREFULLY pop the old rear main seal backwards from its bore at the rear of the engine. Don't scratch up the crankshaft. It sometimes helps to poke a hole it it with a pick to pry it from its bore.
13. Pull the pilot bearing (borrow a puller from the auto parts store)
14. Remove the throw-out bearing from the input shaft of the transmission.
This concludes disasembly.
To re-assemble, reverse the order above.
1. Insert a new rear main seal -- tap into place with a soft faced mallet or a piece of 1 x 3. Tap it until it is flush with the edge.
2. Insert a new pilot bearing into the end of the crankshaft. Again, tap it into place with a piece of 1x3.
3. Bolt on the flywheel -- torque it to specs (borrow a torque wrench from the auto parts store). Then, CLEAN IT with brake clean spray -- any grease or fingerprints = burned spot later.
4. Clean the clutch with brake clean spray. Using the supplied (buy a clutch "kit") installation plug, hold the clutch plate, facing the correct direction, and begin installing the pressure plate.
5. Install the new throw-out bearing on the transmission input shaft -- make sure it is moving freely.
6. Slide the transmission into the spines of the clutch (you aligned the clutch disk with the alignment plug, which should have entered into the pilot bearing and everything should be perfect for sliding the tranny into place -- of course, remove the plug once the pressure plate is bolted firmly into place.
7. Bolt up the bell housing bolts.
8. Bolt on the starter and any other bolts (inspection cover)
9. Bolt on the t-case.
10. Replace the electric lines and breather vent lines
11. Lift the assembly back into place -- use whatever sort of jack you have -- you might have to use a few blocks -- then replce the crossmember.
12. Replace the driveshafts
13. Connect the hydraulic line
You are done...