Hard to give advice when the script is incomplete but from what I have read this is certainly an interesting story. Clearly you will be doing a re-write just as you mentioned but you should purchase a book on formatting so that shots, intercuts, and etc not only make more sense but are also consistent.
Add more description and intentional focus within your writing so that you are telling the story more visually. Allow the action to add pieces to the story and reveal the characters.
Also work on knowing your characters and their motives more intimately so that the dialogue increases their individual depth of character as well as bolsters more organic speaking.
Kudos to you for writing and I wish you the best in your filmmaking endeavors!
-Aaron
