Welcome to the forum! and im glad you like us already
. Well to start out the 245/70's wont really give you want you want. even though they are bigger tires, they are only bigger over stock by about an inch. As for the lift...a real simple way of lifting with a small budget is probably to go with the Daystar spacer lift. Alot of people are going to argue this to wether its a good idea or bad idea. But I had the Daystar kit on when I first lifted my jeep and it was pretty much amazing, It gave me the looks I wanted plus some more ground clearance. And I could definatly fit 31x10.5x15 tires. But people say when you put on a daystar is speeds up the "sagging" process of the springs, the springs are only rated till like 30K or so and then they start to go bad, and the daystar makes that sagging process go fast, which personally I think is total poo. I put my daystar on at 49K, and then I finally upgraded to OME rear springs at 70K and I still have my front daystar spacer and still no sagging yet and im at 73K. With this kit I also had to get new rear shocks and front struts, THESE ARE A MUST if you are going to lift. There are different types of spacer lifts out there for the liberty, I cant really think of all them at this time, plus there are a bunch of coil lifts like the skyjacker, rough country, and Old man Emu (OME). Everyone on here is going to argue that you should go straight to the OME front and rear coils automatically and drop close to 600-700$ right off the back, But the Daystar kit is only about 160-ish, plus new struts and shocks are about 100 for the rear (pair), and 150-ish for the struts (pair), my numbers might be alittle off. But overall total that puts you about 450$.
Now onto tires....theres a question you first want to ask yourself, "Do I want to keep my stock wheels or do I want to go with a aftermarket wheel??" If you are going to keep your stock wheel you have some limits to how wide you can go with a tire bc of the backspacing on the wheels, unless if you add some 1.25" spacers to the stock wheels then you could fit a wide tire (nothing over 10.5" though). But with the height you could possibly be able to fit 32's but thats pushing it, by alot. NOW if you are wanting to go the aftermarket wheel way then id suggest looking into cragars or another type of steel wheel, but you will have to watch bc some 15" wheels wont fit over the break calipers (for example 15" alloy wheels wont fit). With a 15" aftermarket wheel you want something with 3.75"-4.5" backspacing, this will push the tire out alowing you to fit wider tires. There are many different sizes you can get with aftermarket wheels. Just go to www.tirerack.com and look at different tires and a style that you might want and then go to the specs of the tires and it shows you what the sizes are.
I hope this isnt too much to take in at once!
If theres anymore questions feel free to ask!!!
but over time you'll see what I mean