Modify Gantt Chart Dates

Hi,

I recently found a Gantt Chart file / template that I would like to use with one of my projects.

In the the chart, it currently has a date range from 1997 - 1998.

I attempted to modify the X Axis option, but do not see the area to modify the data ranges to 2011 dates. I may want to replace with Fiscal Weeks instead.

How & where can I change these?

I attached an example (Excel 2007) file.

Thanks