Hi, grafxpro...
I can integrate your coupon into your WordPress site. It's actually a good thing that your site is running on WordPress.
WordPress makes it a little easier to integrate a coupon into Facebook.
I would also integrate a function that would allow you to easily update your Facebook page by posting to your WordPress site.
So, I would actually end up coding your coupon into Facebook, plus give you the ability to update all your Facebook fans by posting to WordPress. This would be outside of your regular WordPress site. Too clarify, when you update your main site, your fanpage would only get updated if you wanted it too, or not.
In addition, I speak perfect English and reside in the U.S. I'm also available on the phone and Skype.