Custom ScriptUI buttons that will close the window

For those knowledgeable in ExtendScript & InDesign, I have a ScriptUI question: How can I have a window close properly after the user picks one button or the other when the buttons are custom choices. See the code below:

$.writeln("The user pressed " + chooseOyo("123456"));

function chooseOyo(jobNumber) {
    var machine;
    var getOyoWindow = new Window ("dialog", "Which Imagesetter?");
        var textGroup = getOyoWindow.add("group");
            textGroup.orientation = "column";
            textGroup.add("statictext", undefined, "The current job is " + jobNumber);
            textGroup.add("statictext", undefined, "Please choose an imagesetter for this job:");
        var buttonGroup = getOyoWindow.add("group");
            var o1 = buttonGroup.add("button", undefined, "OYO 1");
            var o2 = buttonGroup.add("button", undefined, "OYO 2");
                o1.onClick = function () {machine = "OYO1";}
                o2.onClick = function () {machine = "OYO2";}

    if (getOyoWindow.show() == 1) {
        return machine;
    } else {
        exit();
    }
}

Fairly simple, no? Well, so far, the buttons don’t do anything and you have to hit [ESC] in order to cancel the window. How can I get this to work?

Answer

EDIT: got the right answer:

$.writeln("The user pressed " + chooseOyo("123456"));
function chooseOyo(jobNumber) {
    var machine;
    var getOyoWindow = new Window ("dialog", "Which Imagesetter?");
        var textGroup = getOyoWindow.add("group");
            textGroup.orientation = "column";
            textGroup.add("statictext", undefined, "The current job is " + jobNumber);
            textGroup.add("statictext", undefined, "Please choose an imagesetter for this job:");
        var buttonGroup = getOyoWindow.add("group");
            var o1 = buttonGroup.add("button", undefined, "OYO 1");
            var o2 = buttonGroup.add("button", undefined, "OYO 2");
                o1.onClick = function () {
                    machine = "OYO1";

                    getOyoWindow.close(); // thats the trick!

                    }
                o2.onClick = function () {
                    machine = "OYO2";
                    }
    if (getOyoWindow.show() == 1) {
    return machine;

    } else {
    return;
    }
}

close() was right. But not using it within the if(win.show() == 1)else{} block. Instead use it within the onClick function of one of the buttons.