[Two codes are suggested]
The previous answers have given well reply, especially the one from Guy Moore. I wonder to recommend two more code.
First one: curie_calculator
Second one: mcsolver
mcsolver: a user friendly and efficient tool implementing Monte Carlo simulations to estimate Curie/Neel temperature
The equation in your question, be it Heisenberg or Ising exchange, can be calculated by Energy mapping analysis. This has to be the most popular paper that discusses this technique. Basically, you consider different spin configurations and map the exchange 'J' into the total energy values from DFT.
In the simplest form, if you have two magnetic atoms in your ...