Ebay developer Improvements – Ebay API

I have been trying to get a list of all current active products after a s**t load of research and practice I managed to get together a script which will list the information I require which is stock available and the sku. Now the issue I have is I have to manually input the ebay id from the website however what I need is to automatically pull out the list of active ebay listings.

Here is the script which will gather the information for a single product.

error_reporting(E_ALL);
    ini_set('display_errors', '1');

    // Load configuration file
    $sandbox = false;
    $compat_level = 753;
    $api_endpoint = $sandbox ? 'https://api.sandbox.ebay.com/ws/api.dll' : 'https://api.ebay.com/ws/api.dll';
    $dev_id = $sandbox ? " " : " ";
    $app_id = $sandbox ? " " : " ";
    $cert_id = $sandbox ? " " : " ";
    $auth_token = $sandbox ? " " : " ";


    $site_id = 3;
    $call_name = 'GetItem';

    // Create headers to send with CURL request.
    $headers = array 
    (
        'X-EBAY-API-COMPATIBILITY-LEVEL: ' . $compat_level,
        'X-EBAY-API-DEV-NAME: ' . $dev_id,
        'X-EBAY-API-APP-NAME: ' . $app_id,
        'X-EBAY-API-CERT-NAME: ' . $cert_id,
        'X-EBAY-API-CALL-NAME: ' . $call_name,          
        'X-EBAY-API-SITEID: ' . $site_id,
    );

    // Generate XML request
    $xml_request = "<?xml version="1.0" encoding="utf-8" ?>
                   <".$call_name."Request xmlns="urn:ebay:apis:eBLBaseComponents">
                       <RequesterCredentials>
                           <eBayAuthToken>" . $auth_token . "</eBayAuthToken>
                       </RequesterCredentials>
                       <DetailLevel>ReturnAll</DetailLevel>
                       <IncludeItemSpecifics>true</IncludeItemSpecifics>
                       <IncludeWatchCount>true</IncludeWatchCount>
                       <ItemID>191744777908</ItemID>
                   </".$call_name."Request>";

    // Send request to eBay and load response in $response
    $connection = curl_init();
    curl_setopt($connection, CURLOPT_URL, $api_endpoint);
    curl_setopt($connection, CURLOPT_SSL_VERIFYPEER, 0);
    curl_setopt($connection, CURLOPT_SSL_VERIFYHOST, 0);
    curl_setopt($connection, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($connection, CURLOPT_POST, 1);
    curl_setopt($connection, CURLOPT_POSTFIELDS, $xml_request);
    curl_setopt($connection, CURLOPT_RETURNTRANSFER, 1);
    $response = curl_exec($connection);
    curl_close($connection);

    // Create DOM object and load eBay response
    $dom = new DOMDocument();
    $dom->loadXML($response);

    // Parse data accordingly.
    $ack = $dom->getElementsByTagName('Ack')->length > 0 ? $dom->getElementsByTagName('Ack')->item(0)->nodeValue : '';
    $eBay_official_time = $dom->getElementsByTagName('Timestamp')->length > 0 ? $dom->getElementsByTagName('Timestamp')->item(0)->nodeValue : '';
    //$current_price = $dom->getElementsByTagName('ConvertedCurrentPrice')->length > 0 ? $dom->getElementsByTagName('ConvertedCurrentPrice')->item(0)->nodeValue : '';
    //$description = $dom->getElementsByTagName('Description')->length > 0 ? $dom->getElementsByTagName('Description')->item(0)->nodeValue : '';
    $itemID = $dom->getElementsByTagName('ItemID')->length > 0 ? $dom->getElementsByTagName('ItemID')->item(0)->nodeValue : '';
    $customLabel = $dom->getElementsByTagName('SKU')->length > 0 ? $dom->getElementsByTagName('SKU')->item(0)->nodeValue : '';
    $quantity = $dom->getElementsByTagName('Quantity')->length > 0 ? $dom->getElementsByTagName('Quantity')->item(0)->nodeValue : '';
    $quantitySold = $dom->getElementsByTagName('QuantitySold')->length > 0 ? $dom->getElementsByTagName('QuantitySold')->item(0)->nodeValue : '';
    $quantityAvaliable = $quantity  - $quantitySold;

    echo "ItemID: ".$itemID."<br>";
    echo "sku: ".$customLabel."<br>";
    echo "quantity: ".$quantity."quantitySold: ".$quantitySold." quantityAvaliable:".$quantityAvaliable;

What I cant figure our is how I can automatically take the listings from my eBay store. rather than having to individually enter each item id.