I don't know what the seminar is, mama...but I'd recommend looking at the library first and reading up about principles of writing for advertising and marketing. You may find you have a good grasp on what you need; if not, at least you'll know it's money well spent.
I'm a FT copywriter. I write content for magazine ads, brochures, Web sites, direct mail, e-mail, video scripts, etc. It can be fun work. I typically work closely with an art director or designer. I also do some freelance copywriting, and it's the same deal. It can be a very flexible job (in fact, I'd like to do it FT from home, just need to convince the boss it's a great idea).
There is a pretty good deal of work available. I really think the best first step, though, is to hook up with a design pro. A lot of people think they just need someone to do layout, and a good designer with a strong grasp of marketing can help sell your skills in. When the outcome is more effective materials, everyone wins.
There are even design agencies that don't *do* writing. You could look for them and sell your skills in to them. Good luck.