Search button

I would like to change the outlook of the searchbutton:
www.debazuin.info/mp3-preken/sermons/0/0.html?limitstart=0

into see attachment.

At the moment I have no searchbutton icon.

Is this possible and could you advice how to do it?

Thanks a lot

Ben

Currently, the form will search automatically as soon as you change (and leave) the search field. As it is in other place in Joomla frontend.
In backend, there is usually a button like in your screenshot.

If you want that button in your frontend, then you need to create a layout override for your template. You can read the basics here: www.sermonspeaker.net/documentation/layouting/21-layouts.html
Bascially you just have to adjust the HTML so it shows a submit button at that place.
With Joomla 3.2 or 3.3 you can create those overrides in the template manager.