How do I make my hobby into a business?

I have a problem now. My little cake hobby is turning into a business. What do I do? I have people that want to get in touch with me to do a cake for them and I do not want my house or cell number handed out to strangers. Let's face facts. If I don't know the name on caller I.D. I do not answer. I am thinking about getting me a web page up and take orders up that way but, I do not even know how to get started. So far I have just been making the cakes and asking for enough money to keep my little hobby going. Let's face another fact, all those little tools of the trade are not cheap. Have no idea how to price the cakes they are wanting either. It is time consuming as well....another fact : I might work up to 8 hours on one little birthday cake. Sometimes have more time in those than I do on a simple wedding cake. I have three cake orders due next week. So far people have been asking through friends to get in touch with me but, with every cake I send to a party my reputation spreads further out into the universe. Help!! Lost and don't know what I am going to do!!! What is the next step to turning your self into a business???