It's impossible to give you specific advice without actually seeing the code behind the contact form. That is something you would probably want to hire someone for.
On the other hand, there are any number of contact form plugins available that would handle this for you. Time spent searching for one with good reviews and that is updated on a regular basis, will save you a lot headaches down the road.
http://wordpress.org/plugins/search.php?q=contact+form
You can also create a contact form entirely in html, if your host provides a cgi script that will handle it for you. But this depends upon your host. This is what I actually do here.