I haven't used Express in a long time
so my advice works perfect for it's big brother (without the "Express"), but may not for Express.
If you hit reply, it will prepare an email with the original text, but without any attachments. If you send it to yourself you will get a copy, and you can delete the original (after saving the attachment).
Or you could always do a <ctrl>a, <ctrl>c, move focus to Word, <ctrl>v, and save it wherever you like.