How can I add front disk brake on my 26' Men's Huffy Cranbook bicycle?

I bought this bike on Wal-Mart and is very nice. I added a motor and now is a motorized bicycle. What do I put or what do I have to replace or done to add front disk brake? I want to keep the wheel/rim sense is blue color to match the bicycle. Also I would like to put one of does classic suspension forks like Stingray,Vintage,etc. to have a smoother ride has well.