The trouble is not with your printer... or even the print settings... the
person who designed the site has designed it for (example) 1024 x 768 pixels
(which is normally the setting for a 17" and over monitor) but you have
letter sized paper. It just won't fit.
Some printers have a "fit to page" option which will 'shrink' everything to
fit on a single letter sized sheet. Some do not.