iPhone 4S ios 6.0.1 update killed my WiFi Range

I recently updated my perfectly functional iPhone 4S from ios 6 to ios 6.0.1.

Since then, I can only connect to my home wifi IF I go near the wifi router, I move 2-3 ft away from the router and the signal gradually dies upon me. The wifi was perfectly fine with a good range before I updated to 6.0.1, which makes me think its the update which borked by Wifi signal.

Before anyone jumps on solutions, here are things that I have tried;

1. Update the Wifi router firmware

2. Change the encryption levels (Open, WEP, WPA, WPA2)

3. Change the SSID (Network Name)

4. Reset the Network settings on my iPhone.

5. Reset the iPhone completely using iTunes.

6. Hard Reset

Nothing. Absolutely nothing has worked, I am not sure what else to do anymore. I brought this iPhone in HK, and because of battery issues and phone not shutting down (ever) I got a replacement when I was in Australia last month. Now I am in India and Apple support here says iPhones dont have international warranty so they cannot replace/repair the phone.

I have lost my faith on ios updates now - any other troubleshooting steps anyone can recommend? Any official Support contact who can help me receieve official Apple support here in India? Anyone? Anything?! This Wifi issue is perplexing me to no end!!!