Thanks for three good suggestions. I'm going to try them all. You all demonstrated your results -- too bad I didn't upload the full res picture, I'd have three free consulting jobs! Just kidding -- then I'd learn nothing.
@Eli I did try the clone stamp, various ways, but always ended up with circular stamps clearly visible in the end result. If not for that, it actually looked pretty good. How do you avoid the appearance of circles from the stamper? I'm not sure what you did in the third layer of your picture. Are you stamping transparency or something?
@IRON67 and @Pixie I'm going to try your techniques. They both look good. I haven't worked with layers much, I will look at those tutorials first. Thanks a lot.