I would like to direct you to three blogs which I think will help what you are trying to do.
The first one is how to do the hover graph in 9.3, even though it isn't a feature yet this blog explains how you can do it
The second and third blog explain how to include charts within tooltips. Its quite a lengthy process with calculations.
Hope these blogs help you decide what you would prefer to do. If you need any further help then let me know and I will do it in your packaged workbook depending on which one you decide
Awesome, thanks so much for the links Lorna!