ToastySpider,
You might want to post your question at the Expression Web Forum:
http://social.expression.microsoft.com/Forums/en-US/web/threads/ .
Be sure to include a link to your site in your post there. That way the gurus over there can give more direct answers. Be sure to read the 'sticky' post titled, "Before Posting'...Read this Expression Web Fourm Posting FAQ..."
I haven't used the gallery capabilities of Expression Media, so I'm not famiiar with how it generates the gallery, but I'm pretty familiar with EW. Create a disk based Web of the site you created in EW, if you have not already done so. Open the Web in EW. Create a folder for the EM gallery files. Open one of the gallery pages in EW and try attaching your style sheet to your gallery page. You may have to add some styles in the <Head>. section of your gallery page (in Code View) to get the layout working for you.
I wish I could be of more help.
Regards,
-Preston
Columbia, CA. USA
http://www.gildedmoon.com