Is there software that can accomplish this with having to reinstall all the data files?
Yes and no. Depends on volume type and easier alternatives specific to your RAID implementation's capabilities (online capacity expansion?).
If the volume type is Basic, partition management software like Acronis Disk Director Partition Manager (http://www.acronis.com/enterprise/products/diskdirector/partitioning.html), Norton Partition Magic (http://www.symantec.com/norton/partitionmagic), Paragon Partition Manager (http://www.paragon-software.com/home/pm-personal/comparison.html), or free open source variants like GParted (http://gparted.sourceforge.net/livecd.php) can be used. Getting hardware RAID support integrated into the open source products for your specific RAID implementation could be a challenge, however.
If the volume type is Dynamic, things are more complicated as dynamic volumes have limited support with 3rd party tools. Backup each volume as would be done before doing any major disk operation with any backup/imaging software that supports dynamic volumes (e.g., Acronis True Image Enterprise Server (http://www.acronis.com/enterprise/products/ATIES/) / LDM (dynamic disks) Acronis True Image Supports (http://www.acronis.com/enterprise/support/kb/?aid=504), Norton Ghost (http://www.symantec.com/norton/ghost) / Dynamic Disk support in Ghost and LiveState Recovery (http://service1.symantec.com/SUPPORT/powerquest.nsf/0/894d4c7d0f66ba2988256e75007ca388?OpenDocument&seg=hm&lg=en&ct=us), etc.), delete and recreate the array(s), and then restore the data. For the downtime, software costs, and work involved, also consider just adding disks and creating another array.