Removal of all viruses in hosting account and all webpages working again

My bluehost account has been hacked and viruses infect all of my websites hosted in this account. I need assistance on removing all viruses and fixing any holes in security so that this may be prevented in the future. I have uploaded clam av to my hosting account but am not sure how to use it to clense the account. I do not have a local copy of all the files because i have small bandwidth issues. Any help is much appreciated.