Zen Cart and Website customisation

General information for the website: We are a bottled water company with the ability to make purchases online
Kind of development: Customization of existing website
Num. of web pages/modules: 2
Description of every page/module: We currently have a website run on Zen Cart available at: www.icycrown.com.au
The follwoing page will need changes:
The product info page which is displayed when you click "order " It has a series of options that are selected prior to purchase.
Description of requirements/features: 1. The product info page needs to be updated to include the following:
A. Each item is required to be filled before the order is accepted. (ie mandatory fields)
B. The layout needs the "5) order" button to be at the bottom not next to the other options.
C. The selection options need to be adjusted to allow for an additional dropbox to appear (or be selectable) when plan is selected. It is to contain 4 plan options of 3,6,12 and 18 months.
When one of these options is selected the price will update to show the full amount. eg: if 5 boxes are ordered for 6 months the total price displayed and charged will be the entire 6 months worth.

2. When the reoccurring payment option is selected (from the same page above), a reoccurring payment is setup through either the NAB transact page or paypal which ever is selected at purchase time.
If this is not feasible then the following could occur: The customer is redirected to another page prior to payment where they fill in their reoccurring details (via an online form)which is emailed to us to enable us to setup the payments manually via the bank website. (This will need to be a secure webform due to the sensitivity of inputting credit card or bank details.
Extra services needed: Customization
Extra notes: