Carbon Calculator for Website

My Client is a Recycling Company in the United States. Here are the requirements: Client would like to add a carbon calculator to their website. 1- They want individuals, families, and businesses to be able to calculate the amount of Carbon Dioxide that they are generating 2- Supporter should be able to purchase carbon credits to offset their impact on the environment. (Paypal or [login to view URL]) 3- Since each carbon credit is used to plant trees, and empty landfills - some nice text or graphics showing the benefit of their contribution would be a nice plus. . The best calculator that I have found is located at: [login to view URL] but if you know of a better calculator or script we are open to suggestions. We need for the supporters of the site to be able to purchase credits, so it will need to integrate to a secure payment gateway. We would prefer that the script be written in PHP/MySQL but the scripting language is not important, just that it works and that we are able to integrate it into Joomla (we can wrap it into an iframe if needed). There needs to be an administrator interface - To see orders. To bid: Please: 1. show me an example of your work, preferably a similar calculator. 2. tell me what language you are using to write the script. 3. tell me how long it will take 4. tell me if you are experienced with Joomla, and how much it would cost to do this as a Joomla component * This is a plus, but not required - I have experience creating Joomla components from stand alone programs.