Hello,
To remove the sub-folder from URLs you could probably use some custom RewriteRule in your .htaccess file, you don't need JoomSEF for this.
But JoomSEF can help you with the .aspx suffix. You can set whatever extension you like for your URLs in JoomSEF, the only thing needed will be to add this extension to the RewriteCond in the .htaccess file again, as Joomla's .htaccess file defaultly supports only .php, .html, .htm, .feed, .pdf and .raw extensions to be rewritten.
As a paid service we can help you configuring or even configure this directly on your website. See:
www.artio.net/e-shop/support-services