Hi Priti
Have you found a solution to this?
One way will be, build a Web Intelligence report on top of the excel file.
Use either Live Office or BIWS connection to get the data from Web Intelligence to Xcelsius.
You can set the refresh option for both Web Intelligence and Dashboard as per your requirement.
Then you will need to provide only the SWF to your user via launchpad. User will have to place the excel file where WebI can access and refresh upon change.
Hope this helps.
Thanks
Runali