No Wi-Fi (greyed out) seems to be a hardware problem. Quickpwn did not touch your baseband and there is NO reason for the wi-fi not to work. Also because it was not the result of the jailbreak process but started out of nowhere.
I had the same problem with my 2G phone. After trying all the possible solution , I ended up changing the comm-board and .............. voila', problem solved.
Your phone is under warranty , have Apple fix it !!!
P/