Need conversion tracking added to my wordpress site..

General information for the website: Wordpress site based on themefusion's avada theme..
Kind of development: Customization of existing website
Num. of web pages/modules: 1
Description of requirements/features: The contact page found on mactribe.co.uk/contact needs google adwords conversion tracking installed. The team at themefusion who created the theme I use suggest using one of the below options:

There are two options for you here, this helpful article on how to use JavaScript to set this up for the built in contact form -> http://www.designchemical.com/blog/index.php/faq/adding-google-event-tracking-to-the-contact-form/

Or making use of the Contact Form7 plugin which has support for Google Tracking & Goal settings -> http://contactform7.com/tracking-form-submissions-with-google-analytics/

I'd like to add the conversion tracking code without editing the theme files if possible, or by using contact form 7 instead to make sure any theme updates / plugin updates in future will not mess with the conversion tracking code installed.

If you're a wordpress whizz, please get in touch!
Specific technologies required: Wordpress
Extra notes: