Fast secure contact form passing param via url to autofill one field

Ok here’s what I’m trying to do.
I am making a humane society site and on the adoption pages I have a adopt button that opens a modal window for an adoption form.
I’ve modified the petfinder plugin to have a unique adopt button and url #?dogname for each pet listed.

first I need help getting the param into the field on the fast secure contact form. I know about the $_get vaguely and is what I was trying to use here. but don’t know how to use that with this plugin (or if you can)

second I was wondering if it was even possible in this instance since technically the form is already loaded?

I could always have it go to an actual page if I had to to make this work. technically it’s not required for the site but it would be cool UI

site is in development still i’ve only been working on it for a few days but figured I would tackle the harder stuff first.

if you want to view it
http://stevepharris.com/hal/find-a-pet/find-a-dog/
user test
pass tester