I've jailbroken it with Redsn0w already, is it fine that I'm using 0.9.10b6 with iOS 5.0.1?

The baseband is 04.11.08, does this mean that I cannot unlock this phone?

I bought an iPhone 4 on craigslist and was led to believe it was for AT&T, but with a little research I discovered that it was a South Korean iPhone. It was not set up so there was no way to see what version of iOS it was running, so I just installed redsn0w 0.9.10b6, but then found out that it was actually running iOS 5.0.1, not 5.1. What do I do now? I also need to unlock it to work on AT&T.

Thanks in advance for any replies!