Invoke PHP search engine from HTML

I have a website who's structure is very similar to wikipedia. It consists of a homepage and a library of hundreds of articles which are just separate HTML pages. I am in the process of building an internal search function and need some HTML, PHP and AJAX support. The search function uses Sphider which is a free PHP search engine. It's already installed and configured and I've already created a MySQL database for it and successfully indexed my website. The search engine is already up and running- you access it at [login to view URL], enter a keyword, and it will give search results from the MYSQL index. I need someone to do the following: Create a search bar that will be at the top of [login to view URL] on my site, that will pass the keyword that is entered to my php search engine and display the results in such a way that it looks like the user is still at the main homepage index.html. I don't care if the page refreshes or if it actually navigates to a results page that looks identical to [login to view URL] homepage, but the user experience should not feel that they have been taken to a different page. This is an extremely basic task that should take an experienced developer less than an hour, including the time it takes me to show you what I have built so far.