Proper licenses for clothing company

I am currently an owner of an incorporation that carries out graphic/web design services. I have decided to start a clothing line under my incorporation but I don't want to use the same name as my incorporation. Do I have to file my clothing company name as a DBA or Fictitious name under my incorporation? Also...I have trademarked the brand name of this company...what are other steps I need to take to protect my brand name and any designs that I'll use on clothing apparel? Thanks to anyone who can help me.