For the CAPTCHA you need to remove this feature from the form within the CSS Form Builder interface. You can edit the form contents and go into the security group to find the CAPTCHA, then remove it.
You do not need to delete the CSSFormBuilder folder when creating a new form or redoing one.
You can add in the extra form elements to make it work with your script and set the action to your page. However, you might loose the ability to have both client side and server side validations in place. To make it work like this correctly you would need to add in the server validations from your form page to the new page you want to post to.
Please post back with any questions that you have about any part of this.