The search functionality needs to be on the homepage, so I can immediately see the benefits of your product.
Also, I think you should be marketing the search functionality and not the button. Make it easy to find a politician's information and then make it easy to contact them and you will find more people will use your button.
There are many sites out there that will get you a politicians contact information. We want to be an alternative that a site like Huffington post, Townhall, CNNPolitics, and others can use to on their site so that their readers don't have to search on another site. It helps publishers out by keeping readers on their page longer, hopefully.
Also, I think you should be marketing the search functionality and not the button. Make it easy to find a politician's information and then make it easy to contact them and you will find more people will use your button.