A website has copied content from my site. What can I do to get this removed?

I have found a website online that has copied an article that I wrote for my own company website. They have made a couple of small changes, but at least 90% (over 1,000 words) of the content is an exact word for word copy. I am obviously annoyed that they have ripped off my work, but even worse is the fact that their copied page ranks 4 places above my site on Google for the main keywords that the article targets. So they are basically getting traffic (and potential business) to their website from an article that I wrote. 

What action should I take to get this content removed? Do I need to hire a solicitor? And if so, roughly how much would this cost?