Adwords Conversion Tracking For Drupal Site

I have a drupal site that I need someone to help me with. The site is an orthodontists site and has a number of signup forms for things link ebooks, coupons and appointment requests. All the forms are handled with modal frame / php, so there is no separate thank you page for each form to install the conversion code on...and also, there is no difference between the thank you page for an organic visitor and the thank you page for a paid visitor.... the site is here...[login to view URL] So, I need someone to help me implement google adwords conversion tracking on this site. Note that I have a multisite setup and will need to be installing this code on future sites, so i would like instructions prepared so that I can install conversion code on future sites. I'm not a programmer, but I'm comfortable enough to install the code on future sites, as long as I know where to put it!