how to modify ramdisk size,kinda urgent !!!

Hi all,
I wanted to know how to modify the size of the ramdisk?
I mean am manipulating a live cd ,for which the file am manipulating is within a ramdisk now due to size constraints i am unable to play around with some stuff....
currently the size of the ram disk is 64M...
I would like to increase its size....
how do i do it?
Also i have very little idea about ramdisks...so wanted to know how it will affect the size of my livecd...
I mean to say...can i fit in a ,say 650mb ramdisk file into a livecd ...
(with all the other dependent files in working state of-course)

Its kinda urgent, so pls reply fast

Sounds like "find the script which creates it, and mod it to make a bigger one right from the start". This is somewhat platform-dependent, but grep for "ramdisk" or "rd" in your init scripts.