Get values from sql table using PHP

This is my PHP code to get values from my sql table. It doesn't work, I'm still search if error is here or elsewhere... Some opinion?

function GetValuesFromDB($username,$password)
{
    if(!$this->DBLogin())
    {
        $this->HandleError("Database login failed.");
        return false;
    }          
    $username = $this->SanitizeForSQL($username);
    $pwdmd5 = md5($password);
    $qry = "Select * from $this->tablename where username='$username' and password='$pwdmd5' and confirmcode='y'";

    $result = mysql_query($qry,$this->connection);

    if(!$result || mysql_num_rows($result) <= 0)
    {
        $this->HandleError("Error logging in. Username and Password do not match.");
        return false;
    }       
    $row = mysql_fetch_assoc($result);             
    $_SESSION['name_of_user']  = $row['name'];
    $_SESSION['email_of_user'] = $row['email'];
    $_SESSION['last_name_of_user'] = $row['last_name'];
    $_SESSION['username_of_user'] = $row['username'];
    $_SESSION['phone_number_of_user'] = $row['phone_number'];
    $_SESSION['address_of_user'] = $row['address'];
    $_SESSION['zip_code_of_user'] = $row['zip_code'];

    return true;
}