The question you didn’t ask was whether the Septuagint is available today?
Yes, there are english translations such as this
amazon.com/Orthodox-Study-Bible-Ancient-Christianity/dp/0718003594/ref=sr_1_1?s=books&ie=UTF8&qid=1395263078&sr=1-1&keywords=orthodox+study+bible
This is a book which is high on my wish list (after I do my income tax). Somewhere, in the last few days, I came across a comment that in your standard Catholic Bible, a quotation from the OT may not actually match the OT verse to which it refers. That’s because the NT is based on the Septuagint, whereas the Catholic Bible publishers seem to want to provide the Jewish Masoretic version, except for the deuterocanonical books, which the Masortic text does not have. This is much more confusing a topic than I thought it was, when I stumbled on to it.
A couple of the gospels may have been written in Aramaic (sp.?) but were passed on in Greek translation, which complicates things, further. Some Greek (and hence modern English) translations are suspect for this reason, that the vocabulary used was not available in Aramaic. Hence, some loss of certainty exists even about the accuracy of the Greek translation, and, hence (again) about what the originals (which now are lost) actually said.
So, as someone noted earlier, your question is a bit of a trick question. As the NT wasn’t written all at once, but only years afterward, and then the texts canonized into the NT for hundreds of years, it’s really hard to say which texts they had and when they had them.
In his book “Tradition and the Church”, Msgr George Agius said (c.1928) that the gospel was spreading far and wide without a written NT. He makes the startling assertion that the Church didn’t even need a NT but which we got anyway, as a divine gift. So, he underscores that uncertainty about what the apostles themselves had and when they had it.