Customising Magento Site

I am creating an e-commerce site, the site enables businesses and their staff to order sandwiches and buffets online. I have already created my own templates and layout for the site but need assistance with customising the way products are ordered and want create the script which does a quick extra calculation in the cart as well as the price. Here is the site, you will need to log in. [login to view URL] Username: getafreelancer Password: xb4g7b The site is split into 3 different services, the services will be split via three large boxes on the front page of the site. The services will be "Design Your Own","Ready Made" and "Buffet Lunches". At the moment i only need help with "Design Your Own" as the other services are more straight forward. I need help on the following: 1. Design Your Own - This service will allow a visitor to design their own sandwich or salad. The "design your own" link on the front page will link to another page with two more options "Sandwich" or "Salad". By clicking on "Sandwich" i then need the visitor to be able to choose a "Bread Type" when the bread is clicked on it needs to be added to the basket and then a list of products associated to the "Bread Type" need to be displayed. The associated products need to be broken down into Sections, e.g. Meats, Dressings, Sauces etc, each product needs to be selectable via a check box, once the product choices have been made they all need to be added to the basket via 1 button, however (and this is where the problem lies) i need the order to be grouped as one item in the basket not all as separate product items in the basket, because the customer may want to order more than 1 customised sandwich. 2. Calorie attribute and calorie subtotal calculator - I created a new product attribute called calories. Each product will have a calorie value (as a number). I managed to get the calorie attribute to show in the grid listing view as well as just the main product view, however, when each product is added to cart i need a total calorie value to show in the mini-cart in the sidebar just underneath the price, this will obviously be needed on a "per sandwich basis" too. The calories values to not need to be carried through to the main cart or the checkout, simply just shown in the mini-cart. In pseudo code, the calculation should be something like this: totalcalories = 0; for each line in cart: get product from line get calories from product totalcalories = totalcalories + productcalories * quantity in cart line end The rest of the site i will develop myself, it's just these two little bits. I am also keen to build a long standing relationship with a developer. Payment will be made on completion of the project.