2 things...

I'm going on vacation today for a week, it's 8:00, I leave at 9:30. 2 hour drive. 2nd thing is, how do I use brightening for areas with a light source WITHOUT the tool for brightening?

Raise the color you have straight up on the color box.

yeah use a brighter version of the main color.. like if whatever the object is is say a medium blue use a lighter blue for the light part of it and a darker blue for the darker parts. and the object also casts a shadow as well =)

you can also do this.........get the color grey....and click the paint mode untill you get "olverlay" then set the brighter or darker level.....51-100 makes it lighter, 1-49 makes it darker.....
Heres a pic to help you out because i dont know the technicle names for any of theis stuff..... http://www.geocities.com/poodlesox/oekpaint2.JPG