Hi Sue,
I have a newsletter that goes out every other Tuesday and a blog that's scheduled for every Wednesday, but my blogging has been a bit off lately. I talk about different things in my newsletter and blog (in other words, I don't duplicate content between the two, but I don't necessarily think you have to do it that way...if it's easier for you, you can use the same article for both your newsletter and your blog), but they both cover the same general topics: marketing and copywriting (my specialty).
I do offer advertising in my newsletter, but I don't really push it and so far I haven't had any takers. Which is fine, because I just use that space to advertise my own products and services!
To get inspiration on potential topics, you can try seeking out other blogs written by professionals in your area of specialty. That way, you might find some "hot" industry topics that you can put your own spin on for your blog posts/newsletter.
PS: You can create a Fan Page on Facebook for your business and post updates to your wall. You start with creating a personal profile, and then you can create your Fan Page. I'm no expert on this area, but there are threads fluttering around the forums on how to do this if you're not sure.