cannot find windows 8 option in GRUB menu after installing 13.04

cannot find windows 8 option in GRUB menu after installing 13.04

I've installed ubuntu 13.04 in a separate partiotion of my hdd which also
has windows 8 in another partition.the problem is, GRUB menu is not
showing windows 8 OS to boot into. so if i want to boot into windows then
i must go into boot priority and change boot order. What should i do to
get windows 8 option in GRUB menu.. and also i cannot access other
partitions of the hdd where windows is installed, similarly cannot access
ubuntu partition when using windows... (I found similar question in thi
section but did not understand it as im new to this platform...)