You don't really need any super special tools for the timing belt. What you need to figure out if you have a crankshaft seal leaking, or oil is leaking past the oil pump housing. That would require two different approaches to repair.
I recall some posts here on the forum regarding the oil leaking past the pump housing. Try to do a search, or go through some old Montero posts.
As far as the timing belt job, do you have a experience with that? Do you have a manual?

 

If you are mechanically inclined and have basic tools and can afford the down time, I suggest you tackle this yourself.

Oil leaking out of the crank that the fan connects to? This makes no sense to me. The fan pulley bolts to a bearing assembly that is simply bolted to the accessory drive, no lubrication involved. Look at 4th picture in Post 115 to see this bearing assembly - note the male pilot on the bearing/flange that mates with the fan pulley.
https://mitsubishiforum.com/forum/mi...-48920/page12/

The 4th picture in Post 122 shows the belts installed and the fan pulley in position.
https://mitsubishiforum.com/forum/mi...-48920/page13/

Look at Post 77 for pictures of how the oil pump seals to the block and the required o-ring. I have read that this o-ring is a common leak source as Hunter advised. The oil pump housing also includes the crankshaft seal.
https://mitsubishiforum.com/forum/mi...l-48920/page8/

When I rebuilt my engine I used a new oil pump with its new crankshaft seal. I also installed a new water pump, hydraulic tensioner, and timing belt. Several of the "kits" include all of these components.