custom newsletter signup form for mailchimp

I have a website that currently runs ProductCart on a Windows server. I have a mailing list using mailchimp. I want to change the signup form to resemble the one on the following website (at the bottom): [login to view URL] except with colors that match my website. The entire code must be able to be inserted into the footer file of the ProductCart website (although it can call en external js file if needed). I do not know what else you need to know to make this work - if you have any questions, please feel free to ask. Payment will be made by escrow, and will only be released once the code is installed and fully tested on all major browsers.