Post Parameter and then Ajax Upload Image Separately

Question

My site is to post status and picture like facebook do. I would like to post the status and after that ajax upload the image separately, however it failed. Any solution for this?

javascript

$('#postIdeaBtn').click( function() {
                    $("#postIdeaForm").submit();
                });

                 $("#postIdeaForm").validate({
                 errorElement:"div",
                 rules: {
                 dateIdea: "required"
                 },
                 messages: {
                 dateIdea: ""
                 },
                 submitHandler: function() {
                 $.post("sites/all/themes/dating/ajaxpages/post-date-ideas.php", $("#postIdeaForm").serialize(), 
                 function(data) {
                     if(data == 'noImage') {
                         window.location.href='date_ideas';//refresh page
                     }
                     else if(data == 'haveImage') {
                        //upload image

                         new AjaxUpload('selector', {
                                action: 'sites/all/themes/dating/ajaxpages/upload-wallpost-image.php',
                                name: 'image',
                                onSubmit: function(file, extension) {
                                    //ext not allowed
                                    if (! (ext && /^(jpg|png|jpeg|gif)$/.test(ext))) {
                                    alert('Only JPG or PNG images are allowed');
                                    return false;
                                }
                                },
                                onComplete: function(file, response) {

                                    $('#uploadImgPreview').attr("src","sites/default/files/"+response).show();
                                }
                              });


                     } 
                    });
                return false;
                 }
                });