You can use localization string macros in your auto responder email. They look something like this:
{$your.custom.localization.key$}
So you could do something like which would be a combination of localization keys AND form data the user submitted:
{$custom.form.hello$} {%FirstName%},
{$custom.form.paragraphtext$}
{$custom.form.thankyou$}
My Company
www.mycompany.com
800-888-8888
Reference Kentico Macro Syntax Documentation