Read resource embedded excel file

Hi

I have an excel file embedded as a resource in my application.  I basically want to be able to open the resource file, write some data to it and save it to a file location.  Not sure if this is possible?  The main problem I'm having is once I have retrieved the resource, I'm not sure how to convert it to an excel format so I can write data to it.

Any help is much appreciated.

Thanks
Adam