Help!!! sick of latest IOS

I got my iphone 4s towards the end of 2011, in about July/August 2012 i dropped my iphone twice in water i got it replaced by apple (happy to pay as it was my fault) the lady at apple told me it was a replacment phone that they sometimes took parts out and switched with, didnt really see the big deal of it. Then i updated my phone to the latest IOS 6 when it came out, my safari started to freeze but it didnt really bother me. A couple of weeks ago i was using my camera and then suddenly it went blank the camera would not open up, as im a person who uses the camera a fair deal this got me really annoyed. I took it into genis and they told me i would have to pay to get it replaced as my phone isnt under warrenty but they didnt know the issue with it. I have found a way to get the front camera to work but it only happens sometimes. One day i was using my wifi and then suddenly it went to 3G, i went to put it back to the wifi but the wifi was greyed out. i need the wifi to work as i cant afford to go over my 3G. Now my camera and wifi dont work i have got them to work sometimes but its really for an hour then they will go back to not working. Is there anyway to get apple to replace my phone as it isn't my fault and is obviously a software problem with the new IOS as i never expierenced an issue with it and from a lot of research ive find my problem has only came up with IOS6. This isnt my fault and i don't want to pay $220 for something that isn't my fault and apple should really acknowledge its fault and replace it regardless if it isn't under warrenty! Please help i need my phone to work again