Nucleobases have been reported in....
... carbanaceous chondrite meteorites, and confirmed as extraterresrial by isotope ratios, (wikipedia here: http://en.wikipedia.org/wiki/Murchison_meteorite), as well as over a hundred different amino acids, although there is still some controversy I believe. The parent bodies of CC meteorites are generally accepted as having had a lot more liquid water activity than comets, so it would make sense that the carbon/water chemistry would progress further there. It's an interesting find all the same though, another piece in the puzzle of where life came from.