How to I protect my ideas when I meet with patent law firm?

I just moved to Palo Alto, CA and don't have any money on my own to file the necessary paperwork; I'd like to meet with patent attorneys offer them a % of the new venture, let them help me incorporate and file trademark, patents and copyrights but I don't know how to present my proposal to them in way that protects me...They can just easily say that they were already working on something similar and take it and run with it and I wouldn't have any resources to fight them...Should I get my proposal notorized? what should I do?