As you know, you can create a formula for each column, where if the month and year match specific criteria, then output the amount, else zero. To show any of the previous months, you have to use 'date math' to calculate how many months previous to 'today' was the transaction created.

To do this, create a formula to calculate the difference (eg. call it MonthDiff):

((Year(Today)-Year(TransDate}))*12)+Month(Today)-Month(TransDate)

Thus, if a transaction was 3 months prior to 'todays date', then the result would be 3.

Then, for each of the columns, the syntax would be:

If MonthDiff = 1 then amount else 0

to print the column for the previous month, etc.