Certified Doulas - referrals from DONA, CAPPA, etc?

I have done the training class, reading and have attended three births working toward birth doula certification through DONA. I side tracked a bit for a part time job but am now back on course. I have some paperwork and breastfeeding class and will finish up certification.

I need clients. I need to market. I am also wanting to add postpartum doula services to my offerings. I have done reading on my own, as well as have experience with much of what a postpartum doula does. I am considering training/certification but it is a cost I cannot afford right now.

Having said all of this, I wonder how many referrals/clients certified doulas receive from certifying agency. If you have input about this, I would like to know. Once I'm certified though DONA as birth doula, will this increase referrals for me? I'm thinking it won't really have significant impact, but I don't know. Following this thought, does it matter which agency I choose to for training as postpartum doula? I am looking at one agency which does not seem well known but the program looks good.

Of course, any other marketing tips would be helpful. I have a website, business cards, brochures but often am unsure where to distribute flyers/brochures. I know these are tough times and it isn't easy to build a new business. Still, I feel confident in what I am offering.

Rondi