Ajax / Jquery with PHP Wizard Needed ASAP

I need help with a project I've already started. A page of 12 products are shown. For each product, I have a box to popup with all the product's info with an "add-to-cart" button. From this popup, when the product image is clicked, it should open larger in a lightbox. This isn't working and needs troubleshooting. Then I would like the add-to-cart button from any of these popups to add the item to the cart without refreshing the page, fadeout the popup box for the product then trigger the sliding shopping cart (the cart is already built and slides down fine). Lastly, on the slide down shopping cart, allow quantity changes and item deletion without the page needing to be refreshed. Let me know if questions. This is a very simple project, so please don't over think it. It's as simple as I say above, probably just a few hours of work. Thank you!! [login to view URL] Click the "cart" button in the navigation to see the shopping cart slide down. Click on one of the products to see the popup that needs help with the images. (It is a work in progress, keep in mind) Also please center the popup box for the product information on the screen regardless of where the browser is on the page, ie right now the box is set to top:100px. That doesn't work if the browser is scrolled to the bottom of the screen. Center the box on the screen regardless of where the browser is on the page. Thanks!