Do you have SHSH blobs saved for iOS version 4.3.3? If the answer is no, then there is no way to downgrade that iPad2 to any other version of iOS. I repeat - there is no way.
Well, I don't have the talent to walk you through the steps. However, thanks to the yeoman efforts of my fellow moderator, f4780y, I don't have to! Please go to this link for a tutorial on how to downgrade a 3G iPad2 to iOS 4.3.3 if you have saved blobs: