wifi not working in ipad 2

Hello there Apple community,

i would like to ask about one major problem.

my wifi is not working at all. it doesnt receive any of signal, it doesn't recognize any of the signal.

This is happen after i upgrade into IOS 6.0. Previously (IOS 5) the signal quality is really poor, only 1 or 2 bar on nearest AccessPoint. Can anyone help me with this? because it is quite expensive to change whole wireless component in IPAD. i think around $250. This is killing me since i always connected to wifi to do my work. Thank you very much