While you have many good ideas here for long term strategy.
Gino's idea is one of the better short term ones.
My approach would be to send out some postcards to your existing client database offering them 15-25% off of any services you offer. Limited time only say 30 days. Exclusions apply i.e. Subcontracted items, or anything under $50. Mail em give em a few days to receive them and, follow up with a phone call to find out if they had a chance to review it. Don't be pushy, just polite. Just opening a dialogue will get the customers ready to purchase talking to you about the project they wanna tackle.
You can easily pad the "discount" into the price if you absolutely have too.
Screw the web (too long term strategy for a short term issue), screw the phone book (useless), screw promo pens. (I sold promo pens for years the only person that ever makes money on pens or with pens. Is the guy selling em and the guy printing them. Never once had a client say a pen got them the first bit of business ever.)
If you really wanna get some attention hand out printed matchbook condoms or, personal lube. May sound out there but, they work. No one ever forgets the guy handing out lube and condoms ever. Have done this for a few clients that didn't mind a shock and awe approach to gaining new business.