Prestashop Order Form and Update Cart

Prestashop 1.4.8 expert and Senior php developer: Order Form Module On the home page, middle column, the following is required. dropdown 1: Select Category (read from table). dropdown 2: Select Sub Category (read from table). Result: Display all Products in a form layout (one row per product) for the selected Category and Sub Category. Above dropdown must be dynamic (maybe use Ajax ?) and the result must be displayed in a form type layout where several products can be selected using a tickbox. A Quantity textbox updates the Price automatically (Quantity x Price = Total) without refreshing the page. Prices displayed must include VAT (tax). Upon submitting Update Cart button at bottom of form all selected products must go to shopping cart and display the Price and VAT separately in Cart same as default. The standard Categories block (normally in left column) must be unaffected and still work normally. If you are aware of such an existing module, we would pay something for the advice, otherwise we need to build a module. The module code must not be copied from another source as we want full ownership of the module code and may resell the module. The module must be compliant with typical rules for building a Prestashop module and should not interfere with the working of other modules. As a Prestashop expert you should have your own site for testing this on. Must be completed within next few days. Full assistance will be given for further explanation.