Calculation to show the final price

[gazustoy]

Good day everyone, I have installed VM2.0'm stuck with a special request from a client, and it shows that once the cart and selected few months are going to pay, I would like to appear on his half as soon as it is indicated Figure 1, so if they choose another payment method to 24 months for example, the division is made.



Same for when the final screen gives you the order of what I'm put my monthly payment.




Any idea what files I have to play to make that calculation?

in advance thank you very much