The best way to fix it is to 301 redirect the incorrect URLs from the error site to the correct site. You need to make a list of all the URLs on mytravelbanners.com and add them as redirects to the .htaccess file for todocomino.info:
redirect permanent /anuncios-gratis-categoria/empleos http://www.mytravelbanners.com/anuncios-gratis-categoria/empleos
redirect permanent /anuncio/oferta-de-prestamo-de-dinero-entre-particular-48h-rapido-y-fiable-emilio-pablo98-gmail-com http://www.mytravelbanners.com/anuncio/oferta-de-prestamo-de-dinero-entre-particular-48h-rapido-y-fiable-emilio-pablo98-gmail-com
This may be a very long list. If the directories don't also exist on the error site, you could simplify this by just redirecting the directories which will also redirect each of their pages individually.
redirect permanent /anuncios-gratis-categoria/ http://www.mytravelbanners.com/anuncios-gratis-categoria/
redirect permanent /anuncio/ http://www.mytravelbanners.com/anuncio/
Then your list of redirects will be much smaller.
With these redirects in place you can safely put up the correct content for the error site.
- Your users coming from Google search will be redirected to the correct place. The only pages for which it won't work will be ones where both sites have the same page URL, such as the home page.
- Googlebot will crawl the error site, get the redirect and update the search index.
It may take Google several weeks to fix the search results. In the meantime it won't hurt the site or users because users will get properly redirected.