Help Help Virus

Well I am tired now. I have three computers in my home and everyday they are getting spammed with spyware and malware. Everday I run antivirus and antimalware and antispyware. Bu the viruses comes again even with no internet usage. I narrowed the problem down and found that my router is infected with Chuck Norris Botnet. I have reset the modem and restore to defaults but it is not killing the virus in the router. I think I have to restore the firmware because maybe the virus is in the firmware memory. I have STC Afaqshamel router and cannot find a firmware for it. How can I hard reset it so it clears the firmware too. I got infected because of default username password. Now I have changed it. I just need to get rid of this virus. As soon as I connect a new computer (friends computer new to the router) it spams it like crazy!