"Buy a new rifle, get new glass, Llama, Maremma etc, etc" - All I can see there is more noise, recoil going up, along with your blood pressure and the bank balance going down!
I agree with CHRONOS. I can't see why your current setup won't cut the Mustard, might have to try a heavier pill in the .223, change the zero but as you have a range finder, hold over should not present too much of a problem, with a bit of practice.
Also, I'd get a gunsmith to check over the 22-250 re barrell worn out etc as this should shoot the fleas of foxes at those ranges..
Good hunting..