Been a while since I've come here... Anyway there's an alternate way I found to get the graphics..
http://www.emutalk.net/attachment.php?attachmentid=32337&d=1145815364That's right, instead of trying to extract the graphics, you play the game straight from the emulator and choose to dump the graphics in the options. That way you'll get all the sprites/tiles from the current area dumped into png's.
Right, the downside? You get a really bad -fps- in the emulator.. Like 3 or 4 frames per second
I haven't tried it since ages and there's a new built released, so there could be a better chance of getting higher fps.
Still if you think you're for the job, get the emu and the rom if you haven't yet and extract the graphics!
Here's a few (I haven't got far because the fps sucked too much at the time):
Of course, some duplicates in there, anyone could make sheets out of them if they wish. Add them to your archive if you want Helios or even better to try the emu if you're patient enough