I'm guessing you're in America. What size is your output pdf? A4? If it
is and you tell the printer to print unscaled, then you're losing the
bottom 2/3" of the page.
First way round that is to tell acrobat to "scale page to fit printer".
Second way is to look at the relevant section of the manual (section 10?
11?) which will tell you how to change the paper size to American
Letter.
As for making everything bigger, change the font size. There's a section
in the manual on doing exactly that - scaling the output for scores,
whatever. Look up "feta" - it might well be in the index, or search the
pdf manual for it. It'll be obvious when you've found the right section,
there's a table of the different font sizes and what they're recommended
for.