Hmm, maybe I should make a 'start your own online website' guide.
It's pretty easy actually. If you already have a product, you're making a good profit from, it should be easy for you.
First off you need a domain name, go to godaddy.com to buy one. Then you need hosting, go to hostgator.com for that. Then change your domain DNS to match what hostgator gives you to have your website on the internet. Your website should be live now, you can go to it's domain and see a default page from hostgator.
Then you use an ftp program, I recommend CuteFTP to manage your website files.
Then you need a shopping cart for your website. It's good to do a lot of research on Online Shopping carts. ONe I like is cs-cart.com
Once you pick out your shopping cart, follow it's instructions and it install it on your website.
Once you have it installed, all you need to do is add your products to it, and configure your payment gateway.
Once you have all that done, and you like the look of your site all you need now is traffic.
The best place for fast targeted traffic is Google Adwords.
Signup for an account at adwords.google.com and create some ads for your site.
Start off slowly with maybe $20 a day in pay per click ads and increase as sales increase.
It'll take you maybe a month to setup everything, but it's really worth it.
Good luck!