Well, the way I got started out is basically by making mention that I am a freelancer to those I met who owned businesses or even friends of mine who worked for small-medium sized companies. I browsed the internet for web sites for local businesses, and for those who had really bad web sites or nothing at all, I'd give them a call or send over a fax. From there, once I got my first handful of clients, I made sure I did an excellent job in satsifying them with my work and my attitude - customer satisfaction goes a long way for freelancers. From there, word of mouth took over and thankfully I've had a steady flow of clients over the past three years. One thing I've noticed is that if you make one client happy, they're sure to spread the word to someone else. I'd say focus on getting clients locally, or at least relatively close to you - it makes conducting business easier and safer (in regard to financial and legal issues).
I would say promot yourself rather than a "company" name. I think as a "company" people have a different approach to doing business with you than as a freelancer. I say promote your name, get a domain with your name and go from there...
Sorry, can't help with the business card size.. but give your local printers a call.
Good luck with your freelancing!
All the best to you.