I'm a 4 month old newbie and also work full time. You have the added challenge of being a single dad. I've learned a lot in 4 months and you will too.
My advice to you is start with the end in mind. To do this you'll need to do some research about all the ways there are to make money online.
There are four main business models,
1. eCommerce where you have a site that sells products and these sites are usually "drop ship" sites or eBay or Squidoo or something like that.
2. Information marketing which means you have your own information product and you sell it online with the help of affiliates.
3. Affiliate marketing where you help sell other people's information products and
4. Consulting/freelancing about internet, marketing, techie stuff or a service you provide.
Then when you've learned about those business models and researched how people do them you'll find the best fit for you.
Other topics you will need to learn at least the basics about are
1. How to generate targeted traffic that you can offer something to so they will sign up for your list (watch out for AdWords when you're a rookie, you can waste a lot of money. Check out how to drive traffic to a capture page via video marketing)
2. How to build a relationship with your followers. Learn everything about Social Media and there's a great book called Socialnomics you can read to help you understand marketing in the Social Media space. There is a lot of etiquette to social media and you don't want to screw that up.
3. How to write copy (emails, autoresponder series, video scripts) so you can communicate effectively.
4. Outsourcing
5. Keyword research and niche markets
So all of these topics can be found on the Warrior's Forum. You can use some of that site for free but I recommend paying the one time fee of $37. It's a screaming good price for membership in that forum.
Speaking of fees, set yourself a realistic monthly budget for building your business (so you don't end up buying all these courses and going in debt) and take the time to draft a business plan to keep you on track.
Happy studying and taking action and good luck to you.