If what I recommend does not work ask the question at http://www.apple.com in the help community.
Turn off your phone completely. Then turn off your broadband modem, and wireless router. If its a combo just need to turn the one unit off. Wait a few minutes. Then turn on the broadband modem let it fully cycle up, then turn on the wireless router and let it fully cycle up, then turn on your iPhone and see if it found your home network. If it did you should be OK.
However there are posts stating that after the iOS7 is updated, the WiFi is greyed out. Some have turn the phone to airplane mode and then turned airplane off again and the WiFi returned. Other solutions have been saying you must turn icloud off.
Like I said the Apple community help forum may have your answer.