Problems with TwitterAPIExchange

I have been having a terrible amount of trouble with using twitter api 1.1. I am getting an error that tells me the '<' from < ?php is unexpected.

Here's my HTML

    <div id="date"><h2>Date/time</h2></div>
    <div id="tweet"><h2>Twiddly tweet tweet.</h2></div>
    <div id="error"></div>

    <script>
        $(document).ready(function() {
            $.ajax({

                type: "GET",
                url: "index.php",
                dataType: "json",

                success: function(data, text){
                    $(data).find('$string').each(function() {
                        var date = $(this).find('$date').text();

                        $('#date').append($('<h2 />', {
                            text: date
                        }));
                    });

                },

                error: function(xhr, text, error) {
                        $('#error').text("JSON Error: " + error);
                }
            });
        });
    </script>
</body>

Here's my php

<?php

require_once('TwitterAPIExchange.php');

$settings = array(
    'oauth_access_token' => "twittercrap",
    'oauth_access_token_secret' => "twittercrap",
    'consumer_key' => "twittercrap",
    'consumer_secret' => "twittercrap"
);

$url = 'http://ift.tt/1As7grw';

$requestMethod = 'GET';

$getfield = '?screen_name=NYCTSubway&count=2';

$twitter = new TwitterAPIExchange($settings);
$string = json_decode($twitter->setGetfield($getfield)
            ->buildOauth($url, $requestMethod)
            ->performRequest(),$assoc = TRUE);
if($string["errors"][0]["message"] != "") {echo "<h3>Sorry, something went wrong.</h3><p>Twitter says:</p><p><em>".$string[errors][0]["message"]."</em></p>";
exit();}
foreach($string as $items)
    {
        echo $date['created_at']."<h2 />";
        echo $tweet['text']."<h2 />";
    }
?>

All I want is the latest tweet from @NYCTSubway, and just the date/time and the tweet, no other information. I feel like I'm missing something simple that none of the tutorials has gone over.