Embed $ Post in Contact Form

I have a site where several Dorpdown menus.
The values are passed to the page with the contact form.
How can I add the values in Contact Form

This is on the input side

<Form id = "calculator" name = "calculator" method = "post" action = "http://www.meine-seite.de/auftrag/">
<Select id = "manufacturer" name = "manufacturer">
     ....
     </ Select>
     <Select id = "device" name = "device">
     ....
     </ Select>
</ Form>