Jewelry Making

I'm looking for advice from any of you who have experience in taking photos of jewelry (or other close up, detail images) on what makes a good camera. I need to be able to take great, or at least good, pictures of jewelry I make. The two cameras I have tried take decent pictures, but nothing comes out well if I'm trying to take a "close up" shot to show detail.

What should I look for when shopping for a new camera?
What makes the biggest difference, lens or body?
Which brands should I steer towards, and which should I steer away from?

And … if I'm shopping with a budget of $900 - what would you suggest?

Get a cheap DSLR with a macro lens, look at nikon, canon, sony, olympus, and pentax models.