Get path of selected file

[lintz]

I've got an option where a user can browse for a file using the code below.

What I want to know is how to get the full path of the file selected?

if ($_POST['submit'] == "") {

?>
<form enctype="multipart/form-data" action="<?php echo($_SERVER['PHP_SELF']) ?>" method="post"> 
File:<br>
 <input type="file" name="file1" size="75"></p> 
<p><input type="submit" value="Post" name="submit"></p> 
        </form> 

<?
}
else {
$file = $_FILES['file1']['name'];
//$file = test.txt
//I want $file = C:\test.txt etc...
echo "File to upload is ($file)";

}

Also, is there a way to restrict the type of files that are displayed when the "browse" button is clicked? eg. only .txt or .csv etc...