Printing each subplot/axes as a separate figure is easier than printing a subset of the axes in one figure. Start with a dummy figure making sure you remember the handle to the axis you want to print:
hax = subplot(2,2,2);
Make a new figure, copy the axis to it, scale the axis to be the "full" size, and print it.
hfig = figure;
hax_new = copyobj(hax, hfig);
set(hax_new, 'Position', get(0, 'DefaultAxesPosition'));
You can copy multiple axes in on go, but positioning them nicely in the figure is more difficult.