Website Virtual Sales Process

Hello, I would like to create an online website "applet", something that would fit within an existing website. The purpose of this app., is to guide a consumer through a series of questions to arrive at a product selection. The product, is a Water Heater. In this case there are only 2 models, so the questions which I would provide the designer, would point to either Model 1 or Model 2. Further, in this applet, I'd like to request the consumer/customer submit a few photos of their current Water Heater Setup. At the end of the process, the customer would be given a PRICE for their project, and required to download and sign a sales contract (If this portion can be done online, we will do that). In the future, this app., would need to be available in a Mobile version as well. What I don't want, is just a bullet question list; it needs to be designed to be somewhat interactive, at each question we can provide some information, examples, graphics etc... So kind of like a powerpoint presentation, that the consumer interacts with, based on their answers, the next screens are derived.