As for color of buttons you will have to add custom CSS(you can use plugin like this http://wordpress.org/extend/plugins/pc-custom-css/ activate it, and next go to Appearance->Custom CSS. There you can insert your custom CSS)
form.contact-form input[type="submit"]{ /* normal color */ background-color: #000000; } form.contact-form input[type="submit"]:hover{ /* hover color */ background-color: #888999; }
Comments
If you want to change contact(add fields) form I would recommend to use some plugin for making contact forms like this http://wordpress.org/extend/plugins/contact-form-7/
As for color of buttons you will have to add custom CSS(you can use plugin like this http://wordpress.org/extend/plugins/pc-custom-css/ activate it, and next go to Appearance->Custom CSS. There you can insert your custom CSS) With regards.