Web Designer/Coder

hi i need someone who can be clever with a shopping cart more than anything here is the situation - our products our appearing as a reader offer next month - readers are able to qualify for a 30% discount and are able to request a free skin care cream dependent upon their skin type so when they have done all their shopping - they enter a promotion code, and then depending on the cream they want they type "dry, oily or combination" then they click submit when they click submit, the shopping cart basket needs to be reduced by 30% and i need to be able to capture what their skin type is within in internal database that i need to be able to view via the admin panel of our website. the skin type needs to be verified against the email address of the buyer/or the order id so as to make sure that the correct free item is being sent out also as per the attachment - there should be another offer (only offer can be used at one time) and a sign up page should be created where people are able to get £5 saving when they purchase 4 or more items this should be quite straight forward queries let me know - only bid if you know what you are doing and if i have queries please be prepared to answer them as opposed to simply posting a bid this project will need to be done with an element of speed thanks