1. Get rid of all of the keyword stuffing on your website. I know it is a large site and this is no small feat but it needs to be done. With your site cleaned and nothing remaining but quality content there will at least be an end in sight to the Google penalty and your site will also benefit from being more readable and usable to a visitor.

2. Begin an ongoing link building campaign now – there is no time to delay. Links are another path to building credibility for your website which it sorely needs right now. There is also a good chance that high quality incoming links will act as additional entry points to your website for Google to index your newly revised site and reconsider the penalty.

3. Review Google Webmaster Tools and attend to any errors/alerts/warnings that Google has provided. Also make sure to submit a fresh sitemap once the site is cleaned so that Google takes notice of any content that may have gone unnoticed and/or new content.

4. Freshen content on key parts of your website with rewrites or additional articles. This will provide positive activity that Google cannot deny adds value to its index.

5. Bolster your Pay Per Click campaigns so they can bear some of the burden during this dry spell of low organic rankings.

6. Be patient. If you do everything I have noted above, you are in a great position to succeed and your site will be stronger than ever before