Short answer: no.
A link is content, which should be handled by HTML. You should not be using CSS to insert content; CSS is meant for styling.
Obviously using content: ”; in our CSS enables us to insert content into our markup and I’m not going to presume to know where the line between correct and incorrect usage is. But I’m fairly sure you should not be inserting a link element via CSS and as such there is no way to do it.
Why can’t you place the link in your markup after the last paragraph?
See here for more info: http://www.w3.org/TR/CSS2/generate.html#content