Complete a web site

Your work is to develop the security system for this site. Site is explained as under:-- The site [login to view URL] offers free domain name for one year. The customers don't need to buy any products to get this once in life offer. All they will need to do is 1) Register at [login to view URL] 2) Get the promo code and the domain registration link 3) Register the domain name for USD 2.95 through the provided link 4) Get back to the site, login and enter the order number along with the domain name they have registered. 5) They get their money USD 2.95 back within 48-72 hours after verifying their purchase via paypal or moneybookers. They are free to transfer the domain names to any other registrant anytime during the year for free. No charges for that. Now this site is functioning perfectly till here. This offer is to be valid for each client only once. So this is what you have to do. Develop a system that:- 1) Record their IP address 2) Work Out with cookies 3) any other security measure that you can take so that the client don't register again as this offer is valid only once per client. 4) Apart from this, you will also need to develop web based mailing system so when someone clicks on contact us it don't show our email address and instead take client to a webform that inturn, mails us the query of the customer. 5) Also I need you to do SEO for this site. The project will be allocated on basis of your experience and after seeing the quality of your proposal. So bid with confidence and give link to your details portfolio. I have tried to explain the project to my best. Any further queries regarding the project can be cleared at the contact details given on our site.