AUTHORIZE.NET CART

My web site is blackdiamondconsultants.us. Clients can now sign up online by clicking on SIGN UP. They send me their info and have the option to print out the PDF contracts through the secured site once the process is done. I want to add a last page to the sign up process which would be the PAYMENT PAGE (following the design already made). I currently accept checks, money orders and the major credit and debit cards. My merchant account online is through [login to view URL] and it is for credit and debit cards only. The charge should be live and request for the security code from the back of the card as well as normal info such as full name (if the personal info could automatically be filled out with the information already provided and be editable that would be great). An option to add a couple of price "discount codes" should be displayed (My client's partners get $50 off and I might add more discount programs in the future). The client has 3 options of payment: 1) one payment of $399 or 2) 2 payments of $199 each (downpayment and 30 days) or 3) one payment of $199 and 2 payments of $99 (downpayment, 30 and 60 days) - which is the most common option. The transaction should be secure and the [login to view URL] secure seal as well as the ssl certificate secure seal I already have should both be displayed on the payment page. A receipt should be sent out to the client's email address (which they have already provided in the sign up process), if they have an option to download it in PDF, just like all the documentation they already do (they could even be on the same pdf file), that would be a plus. The client needs to know how the payment is gonna be displayed on their credit card bill (name of the company and payment dates) - if that could be included with all the other pdf docs, it would be great. Not hard process, just full of details. Last agent which created the web forms (sign up process) already has all the PHP files done, pdf creator installed, as well as header and footer. They just need to be integrated with the last page of the process as well. Message me for more details.