i have a scanned version of this book. it seems good but my non-existent german prevents me from making any real use of it.
there's actually a fair amount of books out there, they are just difficult to find and not the most accessible to the (average) learner.
"georgian: a reading grammar" by aronson and the follow-up book for first-year students "georgian language and culture: a continuing course" by aronson and kiziria are probably the most widely available (and they are also fairly inexpensive). i personally like these books in spite of their heavy emphasis on grammar and passive, rather than active, skills.
georgian intensive course by nikolaishvili - long long thematic word lists, light on grammar to the point where some things were just unclear (or would have been if i didn't have aronson or kekelia to fill in the gaps) and the organization is a bit messy, but nevertheless it's probably good for someone who actually plans to spend some time in the country - situations like shopping, talking about your family, etc are covered and the vocabulary is fairly complete and oriented towards everyday survival.
one more book that i will mention is one that i've heard lots of good things about - "the georgian language for foreigners" - geguchadze. i finally got my hands on this book a year or so ago and it turned out to be a big disappointment. it does not teach any active skills, it is full of reading texts with long lists of words and the grammar explanations read more like...well...excerpts from a reference grammar and not what i'd expect from a good teach yourself book. there are no exercises in this book either, so its only use is as a reference grammar/reading book, and even here it falls far short of aronson.
the other books that i regularly use(d, when i was actually studying this language) are грузинский язык для всех - цибахашвили (georgian language for everyone - tsibakhashvili) and самоучитель грузинского языка - натадзе (georgian self-taught - natadze). kekelia is also a good grammar reference. tsibakhashvili is one of the best imho because it tries to strike a balance between the more difficult grammatical aspects and everyday, phrasebooky things, while natadze is more heavy on grammar, but still very useful and clearly presented.
(one flaw in tsibakhashvili is that not all the dialogues are glossed and even the ones that are don't always give definitions for all the unknown words.)
scans of the last two (and other) books can be found here
there are also some phrasebooky deals like awde's georgian phrasebook or "parlons georgien" - assatiani but these are not really meant for the serious student. the phrasebooks on nukri.org and in tsibakhashvili seem to be more complete anyway.