Thank you for your post.
You should be able to do this with the FileMaker Pro 10 trial version.
Pull down the File menu and select "Export Records". In the next dialog box, you can name the file, and for File Type, select Excel. This will export to an Excel file.
Pull down the File menu and select "Import Records -> File". Select the Excel file, and in the next dialog box, you can select the fields you want imported, and in the lower left corner, you will see the option to Update existing records in found set.
Try this out, and if you have any additional questions or need clarification, please contact me.