DONA might be able to help ... DASC only lists doulas who are certified or in the process of becoming certified and are, therefore, not likely to work for free or low cost.
However, there is http://www.bellywomen.net/ which does provide free doulas AND I can post your request on the DASC group email list (but only with your permission) which does reach the brand new doulas who may be willing to work for free or low cost.
Some birth doulas work for free while trying to become certified, but I don't know of any postpartum doulas who work for free or low cost.
I was in a very similar situation 37 years ago except that I did NOT have my mother to support me -- and there were not doulas then :( Somehow I got through it and I know you will, too :)
Happy Birthing!!!