|You need a primary partition to boot Windows from. So you either need to retain your current one or create a new one. Some disk management software will allow you to convert logical drives to primary partitions (I believe Paragon lets you do this) with certain limitations.|
If you want to get rid of XP (wise move) the best solution would be to reinstall Windows 7 onto that partition. You would probably then need to reinstall GRUB for Fedora. The simplest solution is just to use the XP partition as a data partition. Don't reformat it or you won't be able to boot Windows 7!