I am a big proponent of the Japanese practice of Kaizen – continuous improvement.
One thing is certain – it is impossible to learn all what one has to learn in school. A lot of it will be as a result of self-improvement. This will require dedication. On doing some research online today, I came across some very wonderful resources from LifeHacker. Today, you can watch lectures from top universities for free online, read their lecture notes. A lot these will require dedication. But it is achievable.
Here are some of the resources I found:

1. Massive list of resources from Autodidacts
2. Videos of lectures from UC Berkley – Videos are available from all the prominent departments of the school.
3. Free Art Lessons from Drawspace.com
4. Free classes from MIT Opencourseware
5. Free textbooks from Textbook Revolution
6. Another comprehensive list from LifeHacker
7. Open Educational Resources – This site includes classes for primary, secondary and post-secondary levels
8. ArsDigita University (ADU) – An online intensive post-bachelors program in Computer Science based on the undergraduate course at MIT
9. Online videos of science classes at FreeScienceOnline – http://freescienceonline.blogspot.com/