Its unfortunate that only the first volume is released in English. The chapters have been rearranged compared to the Japanese original in an attempt to make the story more fluid. Unfortunately this might have been the reason TP was only able to release 1 volume in English.
The anime definitely is similar to the novel. I would suggest you read the novel, which is the original source, first, then watch the anime after to further enhance your imagination of what you've read. As far as the art goes, it is basic and simple, which works for this novel. The brief moments of visual art help rejuvenate your imagination and guide you to understanding the author's vision and intentions.
It was an enjoyable read and I hope Tokyopop can solve their problems and release the next couple of volumes.
