Angular use variable before running rest of the code

Question

I know the problem is the order of execution, the scope fires async and loads the data after the rest of the code has been processed. I have a httpGET that gets the information from a web service and it's inside my Facebook share function when the user clicks the Facebook share button. But i tried adding a watch and .then with return promise in the httpget but both i could not get to work.

So the idea is the following: I have an CDImage that the user shares on facebook and i have another directory that holds promotional images for that same CD, not all of them so the httpGET checks if the promotionCDid exists if it exists the variable CDImage should be updated with the CDPromotionalURL instead of the standard url is get from CDImage so the user shares the Promotional image instead of the default CD cover.

So far the problem is that the CDImage does not change directly and console.log(CDImage) displays the CDCover the first time and when you click the button after several seconds the CDImage shows the CDPRomotionURL image.

var CDPromotionalImageUrl = "EMPTY";

 $('#facebookshare').click(function () {

    $scope.GetCDdata = function () {

        $http({
            method: 'Get',
            url: "/GetCDPromotionImage?id_CD=" + promotionCDId,
        })
            .success(function (data, status, headers, config) {
                $scope.CDdata = data;
                CDPromotionalImage = $scope.CDdata[0].filename
                $scope.CDPromotionalImageUrl = "https://website.com/" + CDPromotionalImage          
            })
            .error(function (data, status, headers, config) {
                $scope.message = 'Unexpected Error';
            });
    };

        if (CDPromotionalImageUrl == "EMPTY") {
            CDImage = CDImage;
        } else {
            CDImage = CDPromotionalImageUrl;
        }

        console.log(CDImage)

    var $this = $(this);
    var urlShare = (window.location.href);
    var obj = {
        method: 'share',
        href: (urlShare),
        picture: (CDImage),
        title: 'The ' + CDName,
        caption: "As heard on website.com",
        description:(description)
    };
    function callback(response) {
        //alert("Post ID: " + response['post_id']);
    }

    FB.ui(obj, callback);

 });
$scope.GetCDdata();