Freelance Visa. (Berlin)

Hey guys and girls I am an Australian Artist and Designer who has just arrived in Berlin and am looking to Apply for a Freelance Visa. I understand most of what is required, the question firstly is if anyone here has been through this visa application before and most importantly if so do they grant extensions of the 3 month tourist Visa if im running out of time. Thanks everyone and i hope t get to meet more expats in and around town.