1) is there a way i can increase the voltage through a circuit board, if so, how.
Yes, there are devices called charge pumps or switched mode regulators. White LED drivers often use these devices, due to the higher forward voltage of white LEDs. You'd have to look at some data sheets, but not too long ago I was looking at some LED drivers from Supertex, Fairchild Semiconductor, Allegro, Infineon, and National Semiconductor. Linear regulators like the 7812 will not work off a 5V supply. Some more general information can be found at the wikipedia page on DC to DC converters. I think it is relatively easy to build voltage doublers using switched capacitors, but I'm not sure how much current they can support.
Also, I'm not sure if I would really bother with trying to get 12V, as you probably don't want to run your fans that fast (read: loud) anyway. Sticking with fans you know will start at 5V might be good enough, especially if you have multiple fans.