Hi,
It sounds like your website's search engine positioning has been hit by the Google Penguin update. I think that the first priority will be to examine the cause of that loss of positioning.
In general terms, Penguin has largely targeted those websites that are perceived to have a low quality link profile. Until that link profile is cleaned up, it's impossible to improve the situation.
The clean up process involves:
1. Identifying a full list of incoming links.
2. Highlighting those that are of low quality.
3. Contacting the owners of sites that are currently providing low quality links and asking that they should be removed.
4. Submitting a Disavow File (via Google Webmaster Tools) for those links that cannot otherwise be removed.
Once that process has been completed, the changes will be taken into account the next time that Penguin runs.
My bid would cover the above work.
It should be noted, however, that a full recovery will only be possible if these existing links are replaced by better quality alternatives. This means creating relevant, authoritative, manual links to the site.
I have more than 10 years of SEO experience, so I'm well positioned to deliver results.
I look forward to learning more about your requirements.
Kind Regards,
Keith