I am happy witht eh color of the background when you quote someone, but when you quote a post that has a quote in it, the old quote's background is an off white color. How can I change this?

And I have another question:
As you can see on this forum, there is a white-ish line that seperates the users post, from the users information. What do I change to change that color?

If you have phpBB3, this will take care of the profile separator. Note that if your profile is on the left, change border-left to border-right:

Code:

.postprofile {border-left: 1px solid #204060;}

for the embedded quotes, try this:

Code:

blockquote blockquote {background: #FFFFC0;}

For colors, #204060 is a slate blue/gray, #FFFFC0 is a beige/yellow.