Need a simple custom css to a WP plugin - URGENT

I need to customize this WP plugin: http://yoast.com/wordpress/enhanced-wordpress-contact-form/

As you see, he provides the css code, what I want is just to know where to put the code, this is very simple to a coder.

Send me a PM with your price, I will pay via paypal.

 

I will do this for 5 bucks

 

Thanks Sir Rusty, but, another member responded faster than you via PM and already solved my problem.

Cheers