Grid panel and combobox issue

I'm having issues getting my store on the grid panel to update and render properly from the combobox input. what I mean by this is, when I type into the combobox field, I want it to use the "typeAhead" property and list the selected "displayfield" item, and display the row on the gird panel. Here's my code:

combobox

Code:

var comboBox = Ext.create('Ext.toolbar.Toolbar',{                              items:[{
                        store: store,
                        xtype:'combo',
                        width:350,
                        fieldLabel:'Search Title',                      
                        displayField:'title',           
                        queryMode: 'local',
                        buffer:140,
                        enableKeyEvents: true,
                        typeAhead:true,         
                        hideTrigger:true


                }],
                renderTo:Ext.getBody()
                                
        });

Grid Panel

Code:

 var grid = Ext.create('Ext.grid.Panel', {
        store: store,
                scrollable:true,
                autoShow: true,
        columns: [       
            {text: "Title", width: 250, dataIndex: 'title', sortable: true},
            {text: "description", width: 500, dataIndex: 'description', sortable: true},
                        {text: "Link", width: 350, dataIndex: 'link', sortable: true}
        ],
        renderTo:Ext.getBody(),
        width: '100%',
        height: 350
    });

Store

Code:

 var store = Ext.create('Ext.data.Store', {
        model: 'RssFeedModel',
        autoLoad: true,
        proxy: {
            // load using HTTP
            type: 'ajax',
            url: 'xmlCFFEED.cfm',
                
            // the return will be XML, so lets set up a reader
            reader:{
                type: 'xml',
                // records will have an "Item"
                record: 'item',
                                rootProperty: "channel",
                                descriptionProperty:"description",
                                lastbuilddateProperty: "lastbuilddate"        
            }
        }
    });