While you can't change the color of the text (maybe you can, but I've never heard of this or seen it. Anything is possible i guess), you can add a label to the folder or file. Select the files or folders whose text is hard to read, then select file in the Finder. At the bottom you should see labels. Select a color.
I have the same problems with my backgrounds sometimes, and this is what I do.
Yeah i saw that while i was looking to see how to do the text but i am a person who wants it all done that way not just the ones that are hard to see wish they had black thou