wow wow wow wow wow wow wow... OK now the healing can begin.
First off i see what your talking about. you need to realize you don't have map everything all at once, you can do little individual pieces at a time. good start with the front of the bus and planar mapping it because its pretty flat. What you should do now is select the faces of that little "trim/overhang" piece and the unwrap that with BOX mapping, it should be an option on the right hand side in the Unwrap UVW modifier. This way you make them a separate UV island of their own. Don't be afraid to make UV seems. I would separate the head lights, the sign above, the windshield wiper, and maybe the bumper.
If i were you I would head over to eat3d and really think about buying some of their DVD's... Start with http://eat3d.com/pillar
It covers the entire process of making a high quality game asset. including unwrapping. good luck