Space between widgets

I have installed this plugin calles “Simple Booking form”. The plugin also offers a widget. Now my query is that the widget does not have space below it, like it sticks to other widgets heading or to the footer. Please visit this link to see what I mean http://www.hoteleasternplaza.com/guest-rooms/
Also I want to add a thank you page to whoever fills and submits the form so I can add it to my analytics.