Excel formulas

Hi guys

 

I am struggling with a small problem at work.

Apparently i would need to combine a few formulas but how and what?

 

For isntance, if I have bought a cupoboard for $1000, and the first instalment of $100 will start in april. This means that 4 months are due in 2016, and 8 months are due in 2017 (first row in the attachment)

 

How can I in excel split these 12 months basically or even if was 15 months between the coming years? In row 2, i need to see the "number of months" that the cost will incur that year.

 

Hope it is understandable..

 

Regards

Aina

 

 

PS: My office is 2010.