hi, as for latin literature i'd suggest that you read through all of mackail's history of latin literature online http://archive.org/stream/latinliteratu ... 8/mode/2up
. this will give you context for any reading list you then get.
if you need to learn 4 languages the book you must read for each language is, in my opinion, not a specific book by this or that author, but is the book which is the shortest book you can find ASAP near you which covers the whole ground at a high/basic level. less than 100 pages ideally. read it cover to cover. then once you've read it all the way through read another longer and more detailed one. and so on. starting the process ASAP and covering the full scope at a high level with a short book will help you, i think, more than searching out the perfect book which is long and detailed where you might get stuck in the opening parts which usually deal with how to spell nouns, and not quite get to the rest of the language before you start your course - as a beginner, better to have a good overview of the whole than a detailed knowledge of a little part and no knowledge of the rest of the language. for the modern languages you can also use all the courses that are out there to get some basics into your head ASAP like the michel thomas courses.