Hi there,
A link to a live page may be needed to give exact help.
The submit button has a class of .wpcf7-submit so using something like
.wpcf7-submit {margin-top:20px;}
If using a theme add it to the custom css panel and should move the button down. Replace the 20px for the value you need.
You could add some code to the actual form by wrapping the submit button code in a div and styling.
<div style="margin-top:20px;">[submit "Submit"]</div>
Hope that helps a little
TJ