Probably the easiest way is to make a new document in the required size and just Place (Cmd[Ctrl]-D) the original .indd file in the new one.
Wouldn't the text flow from one page to the next? I want to make sure it stays exactly where it currently is on all pages. Thank you again.
Export a PDF from the original and place that. Scott Zanelli's script will save you a lot of time: InDesignSecrets » Blog Archive » Zanelli Releases MultiPageImporter for Importing both PDF and INDD Files
Making sure "Layout Adjustment" is off (Layout>Margin and Columns, make
sure that Layout Adjustment at the bottom left is unchecked), just go to
Edit>Document Setup and change the page size.