+1 on a good macro lens. That alone will run you a couple hundred. So take a little more time, visit a local camera shop that has several lines of cameras to try out. Really, the best camera will be one that you pick up and enjoy handling and using. I only have experience with Nikon and I've got an old school D40 Kit with a basic lens plus a telephoto lens. It ran me at the time I got it $700 but you can easily find gently used camera kits around that are just as good but will be easier on your budget.
So go slow and compare brands and try out the cameras before you commit. Lenses will be the most costly so this will be an investment.