Hello, I'll be glad to work for you, i can see that your site doesn't have a news module, for a newsletter suscription you will need a news section on your web site.
I could develope the new module for your need, this can be fine for your site since it will help to get more traffic and new customers to you,becausethis will be so attractive to google,bing etc.
I'm web developer experienced on PHP, Mysql, Html, Css, Javascript, i can give good interactivity to your web site and a better your users experience, using these technologies.
Greetings.