Christina I have not done any advertising along these lines and if all I get in return is email in my mailbox then I don't think I will.
On the subject of business cards and other advertising or marketing materials you can try
VistaPrint. They are very good and you can get almost everything free. Seriously, I know they have not made any money on me. I have gotten two boxes of business cards, a couple hundred postcards, magnets, and all sorts of things for nothing.
I think everything MIC6470 said is true. Networking and referrals are the best way to get customers, however you will need to get out there and meet more people in order to expand.
Good luck in all you do and keep me posted. I am here to help any way I can.