By 'the design is a mess', do you mean the HTML content  appears unstyled? Remember that if you normally style content using css, you still need to do the same for emails (the email needs to know which rules to follow). You can achieve this by either attaching the css file to the email itself, or if you'd rather not send your css,  get the email to point at your webserver for its css file(s).
If you need further help, PM me and i'll try and run you through the process.