thanks a lot i'm on windows should i do this on mac???

Hello,
i'm from india i bought my iphone 2g from uae, last month i accidentally updated it 3.1(7C144), it must have also updated my Baseband to 05.11.07.

Now my phone is locked it shows me connect to itunes when i connect it to itunes it shows me to insert a valid simcard, NOTE: in india we don't have At&t or t-mobile

P.S: I can make and receive calls under emergency calls
Please give me a simple and working solution and if possible please provide me with a tutorial
highly appreciated, thank you