Hello,
I can complete your quote button/form for you. I would probably do this as a direct modification to your theme, rather than as a plugin. Would the button appear on all pages?
I see you have a more robust quote form on the site already. If this form is using a plugin already, that's what I'll use as well... perhaps it's contact form 7?
I've looked at the screen shot, what would the form look like full screen? Maybe the form in a modal box, and the rest of the screen dimmed out?
Cheers,
John