Arche,
Ideas:
Find screening material maybe some that were used on old windows?
As for a grow media you could get pebbles or small rocks at river or beach then screen out what you need..I am tossing ideas out.

I bet there is a bunch of unused supplies here and there. you have rivers and streams. Maybe see if old US Navy or Air Force base left any material behind you can get for free? Tell them you are feeding hungry children and stretch it a bit,,,might get response quicker I see your a family of faith so that is a plus on your vision here.

Books...internet is loaded with all kinds of PDF and reading material. I will ask and see if maybe the church would help send a book for you.

I know a young Paster started a neat youthful community based church here in town and they are into "square foot gardening" fro public. Maybe you can Email him? I know he would send a book if you asked. They are a great bunch and he is really into helping out here with Farmers Market and just all around great Pastor (his son is a US Navy Seal too

Serious Arche please Email GORDON the pastor and see if they will get a book for you!
http://www.imaginethisllc.org/