Report and Chart that show sum of new Potentials each week

Report and Chart that show sum of new Potentials each week

I would like to create a Report and a Chart that show sum of new Potentials each week over any designated period of time.

I understand how to create a report that shows all Potentials for any single one week period. However, I want to see a report and bar graph that show...

Sum of New Potentials from 12/31/2007 to 01/06/2008 is XX
Sum of New Potentials from 01/07/2008 to 01/13/2008 is XX
Sum of New Potentials from 01/14/2008 to 01/20/2008 is XX

Is there any way to do this currently? If not, I would like to request this feature.