How can I compare this months performance with last months?

How can I compare this months performance with last months?

I want a report  - better still a graph - which shows the number of potentials added to Zoho this month compared to last month (a month to date setting).  I'd like to see it on a dashboard.  Even a simple this is last months no of Potentials - this is this months (so far).  It would be better if it wasn't always the month - perhaps this quarter or even week.

Is there a way to achieve this?