plugging xbox360 into pc to act as a wireless adapter?

[Matthew]

i have an xbox 360 arcade, i am trying to connect my pc to xbox to act as a wireless adapter,ive done evrything such as bridge my wireless connections together, the only thing i seem to need help with is, when i go to my wireless connection in network settings then click properties then advanced then go to tick the allow internet sharing with other computers, i tick it and click ok, but then it comes up saying for the default ip it needs that there is already a lan connection is already configured with the ip address that is required for automatic ip addressing. can somebody please help me or tell me if its possible to find out and change the ip on the lan computer that is using the ip that my xbox connection is requiring.Thanks