SEO for Joomla website

Optimization of existing language school website in 3 languages (German, English, Spanish)with german being the main language to be ranked on first page of most used search engines like google, microsoft etc. The site contains 4 relevant pages per language. Some things have been done already (ranks already on first page in yahoo) like metatags, info, [login to view URL], [login to view URL] but needs to be reviewed and optimized. Site is done in Joomla so provider has to have knowledge in both SEO and Joomla.