Tejashshah

Hi I'm Using Nexus s for past 6 months but my network coverage is always low and nor do my phone catch up the wifi signal also. even when i'm standing next to my router the wifi strength s jus a single point. and i tried contacting my seller who s from unjha but he s also not responding to my requests so can any 1 pls help me out with tis issue. and even when the update is downloaded the phone gets hanged in between during update showing an !mark on the android and i have to jus remove the battery and restart my phone to put it in working.

Want to update the phone wit the new system update of ff18..... Cn tis update be done? Nd if done hw s it to be done?