First off, backup your data
Download and burn the gparted livecd there http://gparted.sourceforge.net/livecd.php
Boot from the gparted livecd.
Then resize your windows partition and create partitions for Fedora (at least one for / and one for swap).
Then install Fedora on the right partition
(check the size if need be).
Then tell fedora to install grub when it asks. It should automatically detect windows.
Maybe Fedora can even resize (check if you can resize partitions directly from the fedora cd), in which case you can skip the gparted steps.