ipod touch 4th generation not connecting to internet?

i have the ipod touch 4th generation. i usually have very good internet connection, no matter where i am in my house. one day my ipod disconected from the internet. when i tried to re-connect it, no wi-fi network came up. so we restarted the router. it still didnt work. i got on the phone with apple and was told to wipe the ipod clean and restart it. it still didnt work. the only way i can connect is by standing right next to the router. i need help. please.