switch between wifi & phone

[Chillycat]

So i'm at home with only 1 bar or maybe 2 if i'm lucky.

I'd like to download [off the net] sumthin to my i920.

My wireless routers like 3 feet away from where I sit.

I've made all the proper wireless settings on my phone and it
diplays connected.

NOW....... I do not wan't to use the phones connection but want to use the wifi's pipe. How do I disable the phone and make the phone use the wifi for downloading ? I've tried disabling the phones connection but I get that stoopid cell connection error message.

Anyone know the proper method ??