I think if you look in the location:
/galleries/slideshow_dissolve/css/common.css
you will find the .pg-sd-controller css and you can change the margin setting to move it around the page.
if that doesn't work you may need to adjust it in the .js which appears in the file:
galleries/slideshow_dissolve/js/gallery.js on line 104.
this.controllerWrapper.setStyle('margin-top', '-' + ((this.options.showThumbnails ? 40 : 0) + 21) + 'px');
that could be updated to a different margin like:
this.controllerWrapper.setStyle('margin-top', '100px');