post data with curl and change page url - url

Question

I have a shopping site and I have to send username and password and some other data to the bank, so I have used curl for posting data .because it should be safe.
but my problem is when I post data with curl to the bank, page url dont change! I see banks result in my server page !!!
I need this posting data same as posting data in html page redirect too the url which has been determined !!
$data = array(
"MID" => "0113-19",
"RedirectURL" => $SERVER . "/shop/profile.php",
"Amount" => $sum,
"ResNum" => $ResNum,
"username" => "xxxx",
"password" => "1234");
//traverse array and prepare data for posting (key1=value1)
foreach ( $data as $key => $value) {
$data[] = $key . '=' . urlencode($value);
}
$post_string = implode ('&', $data);
$res = array();
$options = array(
CURLOPT_RETURNTRANSFER => true, // return web page
CURLOPT_POST => true, // return web page
CURLOPT_FOLLOWLOCATION => true, // follow redirects
CURLOPT_AUTOREFERER => false, // set referer on redirect
CURLOPT_CONNECTTIMEOUT => 120, // timeout on connect
CURLOPT_TIMEOUT => 120, // timeout on response
CURLOPT_MAXREDIRS => 10, // stop after 10 redirects
CURLOPT_POSTFIELDS => $post_string, // stop after 10 redirects
CURLOPT_SSL_VERIFYPEER => false , // stop after 10 redirects
CURLOPT_COOKIEJAR => "cookie.txt" , // stop after 10 redirects
CURLOPT_COOKIEFILE => "cookie.txt" , // stop after 10 redirects
CURLOPT_SSL_VERIFYPEER => false , // stop after 10 redirects
CURLOPT_USERAGENT => "Mozilla/5.0 (Windows; U;
Windows NT 5.1; en-US; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1" // stop after 10 redirects
);
//////////////////////
$ch = curl_init( $url );
curl_setopt_array( $ch, $options );
$content = curl_exec( $ch );
$err = curl_errno( $ch );
$errmsg = curl_error( $ch );
$header = curl_getinfo( $ch );
curl_close( $ch );