Contact Form 7 Form adaptation

I am using the Contact Form 7 plugin on Wordpress to solicit signups for an event. The form includes fields for Tshirts and other merchandise. Currently, when people submit a form, I receive an email and I then manually create a Paypal invoice for the Tshirts etc. The form needs to be adapted, using javascript so it automatically calculate a final price and on submission, redirects to paypal so the user can make instant payment of the calculated price. Contact Form 7 already allows the user to redirect to a page following submission of the form. This should be a relatively simple job, but I need this completing and live and fully paid up within the next 24hours (it's 8pm UK time now)! I did this on a previous website in around 2 hours, but I have lost the code and don't have time to complete this myself! Please only bid if you can complete within that time frame!