Help with SEO / Site Structure for Google Webmaster Tools

Basically we updated our website to a new version and have included a AJAX filter system for the category pages to help customers find what they need faster. As a side effect we are encountering a huge array of 404 errors and it appears a massive drop-off in our indexed pages and in sales.

We are looking for somebody who can look at our site and webmaster tools and basically update and to undertake work in order to get Google crawling our site and the various url parameters correctly.

We are ultimately looking for a site MOT and to make sure we are up and running in the right direction.

I hope this helps as an introduction and look forward to hearing from you soon.