first we need to know what you have as far as hardware, processor etc as above
go to amazon usb or firewire portables are cheap (intel processor can boot from a usb external drive)
get clone software superduper
clone hard drive
you may not need much, my wife's mb white c2d has 320gb so i bought a 500 iomega which worked for me well in the past
super duper allows very simple recovery if hd dies, and you can make it bootable, namely if something happens to your...