Hello forum!

I need an advice from those of you who are involved in selling products and services online

This may be rather complicated, so first I'll tell you a little about us.
We have an established offline business in little kids (1.5-6 years old) intellectual education, based on a unique system developed by the author of the method, with over 30 books (printed) published and over 12 years of experience in teaching kids at our centers in Europe.
Untill now we only had a regular website (from 2001) telling about us and our positive experience, but we've never promoted it and we rarely add content to it. We've been planning to sell our products online since then and now we've finally decided to start it. There is a high demand for our method, so I'm sure it will sell good. In fact, as you know the two best selling products are farmacy products and kids educational products..

We are planning to sell little eBooks and programs (intellectual games and trainings for kids). They are of excellent quality and it cost us around $100-$200 to produce one such book. We are going to sell it for $5-$10. There will be 20-50 of them.

Now, finally, when you have all the details, the big question is how would you recommend me to promote and sell our products?
I can think of few ways to do so:

1.Built a site, devoted purely to our products and advertise it, but then how should we advertise it? Are PPC search engines good for it? Or should we buy links and ads on other similar sites with high traffic, submit to directories free and paid, including yahoo. Anything else? Is it possible to get top positions at google with these means?
2. Sell our products through ebay or other online stores, invest in advertising and build a site about our company. The question is, of course, will it produce more profits?
3. Build and informative portal about the theme, with directories, forums and so on - to concentrate on providing people with information on this subject and also promote the product, maybe even add adsense or other sources of income. It will demand much more work and higher investment, but will drive more traffic.

I prefer the first way, but I'm not sure of how to promote the site then. So what do you suggest, and also what is your opinion about our plan? Do you believe it can be a success?
Another question is how to recieve payments and make the whole system work automatically ( with paypal or credit card), which scripts are safe and can be intagrated into the site?

I have some experience in programming and webdesign, but I'm a complete newbie in online commerce, so any help or advice is highly appreciated.