Home page background

my site is grm.asia

i got the theme from http://www.wp-templates.com/photo-blog.html
the plugin involved is http://wordpress.org/extend/plugins/better-backgrounds/

home page/landing page background. how do i change it? i am unable to change the background. i have tried background plugins, changing php and css files to no avail. i would like to change it to an image, or make it transparent. when i use the background plugin, i am able to see a tiny outline on the side. meaning the plugin is not faulty, its just being covered by something else in the coding. please help me find the part of the code i have to alter.

i have currently disabled the plugin.