First, welcome to T4R
Second, it's a 4Runner, not a Forerunner (or even FourRunner tho that would be closer).
Third, unless you have lots of mechanical skills and tools, etc, it'll be cheaper to rebuild your 3.0.
There is no "turnkey" swap for the 3.4, there's a lot of custom work involved.
Spend a little time Searching here and on the web for 3.4 swap, and you'll find out what's involved.