You mean your rank is down to 700 from being the top 2? That IS serious. Have you considered fixing your site's content? Take note that what Google wants from websites now is the quality. You could read through the update posted on Google's Webmaster Central blog, and maybe scan some of the comments.

Official Google Webmaster Central Blog: Another step to reward high-quality sites

As the previous poster started, the first place I would look is your content... are you catering to an english market? Does your content flow as if a fluent english writer created it? Take note of these things, and inspect your site backlinks as well.

How old is the website? What kind of prior linkbuilding has been done to it? Does it have an kind of social presence?

If your website has static content then you have to do seo for your site.

Post fresh quality content on your site, and then try to get backlinks from high pr relevant sites to those contents. it'll help you to..

I's not a panda update. It's an algorithm update btw