Form Submit Opening A New Window & Forwarding On Main Site.

I want a form that people fill in their name, email address then click a banner to submit the information to my site admin email address but as they submit using the banner, I want the site the banner is advertising to open up in a new window while the main page will go to a 'thank you' page.

Does anyone know how to do this?

So far I have this:

<form method="POST" action="http://...a php form" >
<p align="center"><span class="style6">Name</span><br>
<input type="text" name="Name">
<p align="center"><span class="style6">Email</span><br>
<input type="text" name="Email">

<p align="center"><input type="submit" name="submit" value="Submit">
<p align="center"><input type="image" src="http://..image" alt="Submit"> </form>