Definitely not enough, maybe only 2-3 hours per work which includes responding to potential clients by e-mail, blogging and refining the copy on my landing page.
Thanks James. I wanted to see what you must be doing in those 2-3 hours/week, so i just checked your website and twitter account. What you are doing with "customer feedback day" is awesome, very few people in freelancing/small-agency setup do lead nurturing and i believe you are one of those.