[DIYbio] What is a efficient way to get lots of own my DNA?

Dear DIY-biologists,

i need lots of my own DNA for experiments at school. The 'research' is about to find out using chemical detection reactions that carbon, hydrogen, oxygen, sulfur and nitrogen are the elements in my DNA . The method i used to get DNA does not produce enough. I used a method similar to this but with spiritus instead of pure isopropanol(worked better). The problems i have with this method are not only the small number of macro molecules i get, but also that i could have bacteria DNA in my sample. I am also lacking a method to dry the DNA.
So now my question:
Do you know a good way to get human DNA?
Good includes
 - nearly no bacteria DNA
 - Can do at home,( with chemicals from school lab)
 - Much DNA per Time
 - Can do in many iterations
 - No pain, for human subject :-)
 - My own DNA, no sample replication with nucleo acids, thermocycler or so
 - a procedure to dry DNA without destroying

Thank you for your inspirations and ideas