While it appears that the Sparrow.sys driver is hard coded for IRQ 11, you can change the IRQ assignment by using the registry.
Use Regedt32 to navigate to:
On the Edit menu, Add Key name Parameters.
Select the Parameters sub-key and Add Key name Device#, where # is 0 if this is your only adapter (see HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port #).
Select the Device# sub-key and Add Value name DriverParameter, as a type REG_SZ. Set the string data to IRQ=12 (or any valid IRQ)
You must shutdown and restart Windows NT for this change to be recognized.