Customization in virtuemart

Hello, I work as a project manager in a marketing solutions company, we are working on online curtains store and need someone to make some modifications to the Virtuemart product page. We need the user to calculate the total cost of the curtains of filling some specific information like window width and height, also we want the user to select which part of the curtain he/she need to buy like the drapery or sheer. Finally, we need to add the payment with Visa option and make sure that the website is secure enough for online payment. To make it simple, here is a live example that we want to make the same page in our website [login to view URL] I'm ready to answer any questions, please reply me with the estimated budget and time. Thank you