Login Redirect Problem

I'm having a little trouble redirecting a user to their profile.

I need to direct them to:

usergallery.php?username=usersname

But instead it's just directing them to

usergallery.php?username=$username

<?php 
session_start();

$dbHost = "***"; // Database Connection Details - host
$dbUser = "***"; // Database Connection Details - username
$dbPass = "***"; // Database Connection Details - password
$dbname = "***"; // Database Connection Details - database name

$username = $_POST['username']; // Stores our inputted data in these variable names
$password = $_POST['password']; // Stores our inputted data in these variable names

$db = mysql_connect($dbHost,$dbUser,$dbPass); // Connection Code
mysql_select_db($dbname,$db);                 // Connects to database

$query = "SELECT username, password FROM users WHERE username = '$username' AND password = '$password'";

$result = mysql_query($query, $db);
if(mysql_num_rows($result)) {
   $_SESSION['loggedin'] = 1;
   header('Location: http://www.mydomain.com/lisa/usergallery.php?username=$username');
   exit(); } 
else {
  echo "<script>alert(\"The username/password did not match.\");</script>";

   exit(); }
?>

PHP:

Would be very grateful for any help.

 

Fixed thanks.

I put ' instead of "

 

You might be wrong here i guess.

header('Location:http://mydom.com/lisa/usergallery.php?username='.$username);

PHP:

Cheers