I have no experience with the RAID setup, but the Win 7 Backup and Restore utility will make a backup image of your system. It can then be restored to a different hard drive, so I would hope it would work on a RAID setup, but I have no way of knowing for sure.
Will it fit on a 500 G drive, depends on how much data you have, but the restore process puts it back exactly as it was found with the original partition sizes.
After you make the image, you might want to test it by restoring it to the other 1TB drive first.
I suppose you have the RAID drivers and know how to add those during the install...
Operating System Win 7 x64
Computer Type Homebuilt
OS Service Pack 2
DirectX Version 11
CPU Type and Speed i7 3770K
Motherboard Chipset Asus P8Z77-V Pro
System Memory Type 16 GB Kingston
Video Card Type and Speed Nvidia GTX 680 (2)
Computer Monitor LG 27" (3)
Hard Drive Kingston 240 SSD
Optical Drives LG WH12LS30 Blu-
Modem-Router Type Linksys E3000
Network Adapter Intel Gigabit
Anti-virus Software MSE
Computer Skill Level Average Ability
Windows Experience Index 7.7