I graduated with a bachelor's degree in mathematics in 12 years ago. Then I started working as a professional computer programmer. So now I can use computer and applications like MATLAB.
I want to return to the world of mathematics; try, understand and see inside it with using technology. I think I have to start with calculus again and deep in it. Now I look for a map which includes list of free PDF files to help me to achieve to that goal also for open source applications to help me see more things after images in PDF files (my English listening is poor so I do not look for videos)
I found a 2 volume work on mathematical analysis which I would highly recommend, given your background. It covers everything in a standard calculus course and a bit more, but is written in a more formal, rigorous style, suitable for a mathematically mature reader. I personally sought it out because I wanted a more rigorous reference for calculus than the typical standard texts and am very pleased with it.
It is Mathematical Analysis I and II by Vladimir A. Zorich, it can be found online at: http://math.univ-lyon1.fr/~okra/2011-MathIV/Zorich1.pdf and http://math.univ-lyon1.fr/~okra/2011-MathIV/Zorich2.pdf