Add to cart button alignment

Sounds like a CSS conflict. Use the developer tools in Firefox (or Firebug) or Chrome or Safari or IE to see what’s loading on your site and how to find a conflicting CSS selector with display:block or something that is breaking the layout.

Other than that, Atelier is a premium/paid theme not supported in these forums. It’s best to go to the support site where you bought the theme http://www.swiftideas.com for help with customizations and issues. You paid for support when you bought the theme, so you should contact the people who sold you the theme.

These forums are for free themes available in the WordPress theme directory at http://wordpress.org/themes/. See http://codex.wordpress.org/Forum_Welcome#Commercial_Products