How can I unlock my iPhone 4S using R-Sim II if I already upgraded to iOS 5.1?

I bought the R-SIM II unlocker without checking to see if my iPhone was iOS 5.0 or less. Is there any way I can still use that unlocker, even though my phone is iOS 5.1? Would I have to downgrade the iOS, unlock it, then re-upgrade it? And if so, could you provide the links that I need to do it? I really don't feel like buying the newer version of the R-SIM.

I am not aware of the unlock that you have specified.You can unlock the phone with the latest OS itself.I suggest you can approach Classicunlocking.com and specify the country,locked network of iPhone 4S.Based on the availability you can get the permanent unlock service along with free instructions.