I’m not sure what you mean by “so basic and unprofessional ” but there are ways to do this. First, there are plugins that you can use, or you can use a child theme and some custom code without a plugin:
http://wordpress.org/search/change+login+page
If you know basic HTML, CSS, and a bit of PHP, I would opt for the latter way. Otherwise, plugins (though limited) are the way to go.