First Banner Ad - Stuck and Advice Is Greatly Appreciated

Hi,
I've contacted some relevant blogs in order to advertise to sell my book (The Web Design Workbook for Dentists) and I was given the opportunity to put a 240x80 banner ad on the website for a month for free.

The problem is I have no idea what to say!

What I'd really like to do is:
1) put a picture of the cover (like I have on my website)
2) put the name of the book (The Web Design Workbook for Dentists)
3) and get people to check it out ("Download a Free Sample Now!")

[naturally one needs to signup for my newsletter to get the sample -- with no small thanks to warriors here for that one]

Clearly I cannot put all of this on there so I'm lost with what to do.

Here is a link to the image I'd like to use that I currently use on my website at full size, but of course I will need to scale it down -- to the point where you can't read a darn thing.

Should I just go with text? I feel like I need to put a picture but why waste valuable space with a picture nobody can clearly see?

Would it simply be better to do this:


And when they click the banner they will go to my sales page (which has the option to download the sample content).

Thanks in advance for your advice!