I'll suspend my lurking to try to answer that.
"Just a dream away' can be translated literally in Italian:
"lontano solo un sogno", but because you have not provided the context there is a serious risk that the translation will not make any sense to whoever you want to say it (a woman, right?
).
If what you mean is something akin to "Our life together is only a dream away", then a good translation would be "La nostra vita assieme e' lontana solo un sogno", which sounds nice but does not make much sense, since in Italian, as in English, a dream is just a dream, something not real and in most cases unreachable.
Aw, I'm not helping much, am I? What about some context?