Cumulative values - actual plus budget values

Hi all,

I've a list of costs. 

The list contains a column with date and other column that refers if the cost is budget or actual.

I would like to create a graph:

 X axis: months

 Y axis: cumulative values 

The graph should be perfect if the cumulative values over the months uses actual values to create the cumulative bars on the past months and for future months the cumulative values should be the sum of actual values plus the budget values.