wow... nice work.
Lots of the companies that make 3rd party renderers for 3ds and maya also do cut down versions for sketchup. Eg vray, maxwell, indigo. Do a search for "vray sketchup"..
eg
(not my work)
This was modelled in sketchup and then rendered with that vray for sketchup plugin.
keep going ... you'll get a job in architectural visualization in no time.