change font size of PDF document in Acrobat Professional 8

HI

I'm facing a problem while reading PDF document in reader.

Problem Description:

Since I'm having 10" laptop, while reading e book i would like to increase font size of pdf document instead of Zoom in. Because if i "zoom in", i have to scroll horizontally to read each line.

to achieve this, I tried the option "Advanced Editing -> TouchUp Object". By this tool, if increase font text of selected text, these are getting overlapped without increasing page number of pdf files.

i tried to change "page setup". i could able to change only for newly creating document via " New Document" tool bar. But not for existing pdf document.

MY Wish:

while I increase the font size of a PDF document, it has to increase size of font without giving horizontal scroll bar. But it might increase no of pages if need like MS Word.