See the list of supported camera raw formats:
The raw support for D7000 is only available with Aperture 3, sorry.
If you do not want to upgrade to an Intel machine, DNG Converter is your best option, but Aperture would be able to profit a lot from a faster hardware with more RAM, better graphics Card, and a modern processor - you would certainly appreciate the difference .
DNG converter keeps the raw bitmap and the exif information stored with the image, but I am not sure about camera specific processing. Usually the raw converters supplied by the manufacturers can do more, to preserve camera specific in-camera optimization and preprocessing.
I don't have your camera, and I am using aperture 3. For the cameras that I tried the free adobe DNG converter with (Lumix, Canon EOS D5) the results are quite o.k., I got high quality raw, without any in camera settings.