Add these to your sources.list
nano /etc/apt/sources.list
deb [arch=i386,amd64,armel,armhf]
http://http.kali.org/kali kali-dev main contrib non-free
deb [arch=i386,amd64,armel,armhf]
http://http.kali.org/kali kali-dev main/debian-installer
deb-src
http://http.kali.org/kali kali-dev main contrib non-free
deb [arch=i386,amd64,armel,armhf]
http://http.kali.org/kali kali main contrib non-free
deb [arch=i386,amd64,armel,armhf]
http://http.kali.org/kali kali main/debian-installer
deb-src
http://http.kali.org/kali kali main contrib non-free
deb [arch=i386,amd64,armel,armhf]
http://security.kali.org/kali-security kali/updates main contrib non-free
deb-src
http://security.kali.org/kali-security kali/updates main contrib non-free
then apt-get update