ExcelBanter - colors change in graphic

Dear,
i have a excelsheet with data that is imported from acces en excel.
In this excelsheet i need a grafic with that change color if the some
imported data change and go above data.

The data is:
the results of the month of this year.
the results of all months of last year
and the budget of those months.

The Graphics is a simple grafiek with 1 line and 1 block for every month
that
is past for this year.
The line is the budget.
The blok is the result for month x (in total ad the end of this year there
are 123 blocks.
Now my question.
Can i let the coler of those blocks change.
The change is as follow:
If the month result is higher than budget = Green
If the month resukt si lower than budget but higher than 2010 = orange
It the month reuslt is lower than budget and result 2010 = red.

How can i do this please.
thanks in advange.