An Old Man Emu kit will take you up 2 - 2.5" and allow you to run 30" tyres off-road. You won't need to think about re-gearing either.
As minimog says you can go a lot higher, but then driveline vibrations become a problem, which means a bigger spend, and if you go bigger than 31" you'll definitely need to think about re-gearing, which is yet more money. The OME kit comes with a Transfer Case drop kit to cure the vibrations, and the performance and engine braking you lose will determine whether a re-gear is required. You can fit up to 31 x 10.50 tyres on the standard rims.
Just decide what you what to do with it, what size tyre that will require, and the suspension lift size will follow from that.
The steam from under the bomnnet might be something a simple as the radiator fins being clogged with mud. Try a hosepipe from behind the radiator (not a pressure washer, as that will damage the fins) to clear the crud. Also worth checking that you haven't got mud in the cooling system via the expansion tank.
