Legal advice in regards to a written piece of work?

last year a friend and i came up w/ an idea for a film. we wrote it down, signed and dated it! a lawyer told me to keep that in a safe place. I wanted to write the script for it, but she didnt pose any interest in it at the time, so i consulted my best friend's brother cause hes a film studies guy and play actor. i asked him if he would be interested in helping me co-write it? he said yes. for the past few months we've worked on it. To his own admission i am the better writer than he is. The story has kind of gotten out of control and its turned into crap! the stuff and ideas he has for it are horrible! i cant believe this has happened so fast! He set up a website because we were planning on making a promotional trailer for it, even though the script is not done. He put his name all over everything on the website so it looks like its basically his whole deal and I'm barely even mentioned and it was my idea in the first place! very pissed!! hes already held auditions for actors to work for free and stuff. He gets downright nasty and demanding with me because he is the ';director'; of the trailer. I was thinking of just writing the whole thing myself and sending it in that way to be copyrighted under my name since it was pretty much all of my idea and with him he's tryign to control the whole thing with his bad writing and bad ideas. Would there be anything wrong with me writing it, giving it a diff title and giving credit to me and girl who's idea it was in the first place? can he sue me or anything if i dont use any of his ideas or words in the script that i write? if i give it a diff title could he still steal the concept and make a diff movie? its a hard concept to copy. does that piece of paper that she and i signed last year after completing the basic story/concept have any effect at all? give me your opinions pleaseLegal advice in regards to a written piece of work?
You keep using the word ';idea';.....ideas can't be copyrighted/trademarked, etc. Any ';idea'; for a script has already been done 100 times.





As far as the rest.....next time get things in writing. Eliminates all these problems.