OSCommerce Shopping Cart Help

I have an OSCommerce site and I need some work done to the Shopping Cart / Shipping section. ? I need the Shipping to be formatted like this: 1st Item - $7.00 Standard Rate Every Item on top of that should be $3.00 per extra pound. I also need Shipping to be Free if the total order reaches $150.00. The Checkout process should also have a Coupon Code module installed. ? I want to be able to create coupon codes that the customer can enter at the time of checkout in order to get a discount. ? Either a total amount off or a percentage of the order off. There should also be a text box in the checkout process that users can type in how they heard about us. ## Deliverables 1) Shipping Module adjusted to have a $7.00 Standard Rate then increase by $1.00 increments for every extra pound. 2) Coupon Code Module Installed. I should be able to assign coupons that customers can enter during the time of checkout to receive discounts in one of two ways. a) A Percentage Discount off the total Sale b) A Cash amount off the total Sale 3)Text Box added to the Checkout Process where customers can enter "How they heard about us" ## Platform OSCommerce