Change animation speed

I am creating a new "whack-a-mole" style game where the children have to hit the correct numbers in accordance to the question. So far it is going really well, I have a timer, count the right and wrong answers and when the game is started I have a number of divs called "characters" that appear in the container randomly at set times.

I have taken away the "play" button and have replaced it with "easy", "medium" and "hard". When a mode is clicked I want the speed to change. The three button share the class "game_settings"

Here is the code that makes deals with the animation

function randomFromTo(from, to) {
    return Math.floor(Math.random() * (to - from + 1) + from);
}

function scramble() {
    var children = $('#container').children();
    var randomId = randomFromTo(1, children.length);
    moveRandom("char" + randomId);
}

var currentMoving = [];

function moveRandom(id) {
    // If this one's already animating, skip it
    if ($.inArray(id, currentMoving) !== -1) {
        return;
    }

    // Mark this one as animating
    currentMoving.push(id);

    var cPos = $('#container').offset();
    var cHeight = $('#container').height();
    var cWidth = $('#container').width();
    var bWidth = $('#' + id).width();

    var bHeight = $('#' + id).css('top', '395px').fadeIn(100).animate({
        'top': '-55px'
    }, 6000).fadeOut(100);

    maxWidth = cPos.left + cWidth - bWidth;
    minWidth = cPos.left;
    newWidth = randomFromTo(minWidth, maxWidth);

    $('#' + id).css({
        left: newWidth
    }).fadeIn(1000, function () {
        setTimeout(function () {
            $('#' + id).fadeOut(1000);

            // Mark this as no longer animating                
            var ix = $.inArray(id, currentMoving);
            if (ix !== -1) {
                currentMoving.splice(ix, 1);
            }
            window.cont++;
        }, 1000);
    });
}

How would I make it so that these settings change in acco