Can I have 2 (or more) charts in my Windows 7 gadget?

You can continue to add charts, by entering the chart ids for each chart into the widget options box. To access the widget options, click on the LilySlim widget on your dashboard. When you have finished entering chart IDs click on the Update widget button to see your new charts.

multiple charts
You can change the order of your charts by, moving the chart ids around.