If it's not included with the operating system, the scanner manufacturer is responsible for supplying either a WIA driver or TWAIN driver for specific models & Windows versions. Since Canon have no Windows 2008 Server drivers for your model, and the Windows 7 driver only "partially works", if you are using USB interface you may want to try "VueScan" software:
http://www.hamrick.com/
Download the free trial version to see if it works with your scanner.
Before installing VueScan I suggest you remove the Windows 7 driver first, then tell VueScan installer that no other scanner driver is installed. VueScan will then install it's own generic scanner driver.
VueScan must be purchased if you want to keep using it (if it works of course).
Please note: VueScan only works with scanners connected via USB, not parallel port or SCSI