Please forgive my complete ignorance, but I need your help!

I am suffering from severe brain damage due to a fall down a mountain, head-first into an ice wall, and need help with my 1989 2-Door, V6 Dodge Raider (I have no way of knowing, but I expect it is unmodified--a "stock" 1989 Montero with a Dodge label.) I have read through many posts but I need to start with four VERY basic questions:

Question 1:
I need new tires but I do not know how to tell what size my rims are. On the rims right now are a set of 235/75R15 Pirelli Scorpions. How can I tell what size the rims are?

Question 2:
Once I know the rim size, how do I determine which tires will fit my rims? I have done a lot of research and believe the:

Special Service Super Swamper TSL Size 34.9x9.50-15 LT Black Letters Load Range C,

are the best for me: I need a tall, narrow tire, with monster tread and very strong side walls.

Question 3:
How can I tell if these tires will fit on my Raider, and if I need to raise the body to take them, what is the best way to do so and what is the cheapest way to do so? I would prefer to raise the whole suspension/frame, not just the body as I need as much clearance under the Raider as possible!

Question 4:
As I will be increasing the tire size, what can I do to change first gear to move at as slow a crawl as possible?


FYI, the Raider will see almost no road use and will be used in very remote, very rocky locations. The next set of questions will be about putting two sets of ARB Air Lockers on it (front and rear).

Thank you so much for your wonderful site!