Adding a shipping calculator based on zip code needed

[login to view URL] We are needing someone to help us add a shipping calculator to our site using UPS and USPS. We had it installed on our previous site. We want to match it as close as possible. [login to view URL] Add item to cart and click on 'estimate shipping' button to see the example. It bases the shipping cost off of their zip code. We currently use WP Shopping cart in our wordpress site. [login to view URL]