Facebook.... I don't know. Tried that and didn't see much results. Google adwords work, but the effect is only good until the money runs out (which doesn't take long).
Personally I've found that the biggest things that get the data recovery work is:
1. Mailing out a small pack of brochures to every computer repair shop in the area.
2. Follow up by stopping in and introduce yourself in person / drop off more brochures
3. Follow their Google+ feed, post an occasional comment, +1 something, and hope they follow you back.
4. If they refer someone who's drive you recover, call them and thank them / ask who to send the 10% commission check to.
5. Tell them about the 20% commission they could be getting if they become a partner (and are willing to put an image/link to your site on their homepage)
6. Linkbuilding, Content Building, SEO, the works. (best long term strategy for getting distant work and random customers).
I'd say that right now 60% of my work is from the PC repair shops and 40% from the web or past clients referrals. I'm hoping with more SEO work to get those numbers to flip so I'm getting more from the online.