Copywriter to improve site content

I need to improve the content of my website (SEO) and then have written a mailer to send out to a database to increase traffic to my site and bring in more prospects / opportunities. Website first, mailer second. Both are important, but they only really work in conjunction with each other.
The content is OK, but poor grammar, lack of making knowledge and SEO are holding the site back. My message needs to be more punchy..