Speed of websites

We manage a number of websites however we are having problems with the speed of them as tested with [[login to view URL]][1]. We require are websites to load in under 4 seconds. We are looking for a coder to work with us and optimize our sites that are a mixture of html, wordpress, joomla and magento. We shall put up a project on VWorker for each site, this bid should be for one site, for details of this site please reply and we will send the url. When you are replying please give an example of a website which you were responsible for coding that is speed optimized. Thanks!