We have been hacked by [S.W.T]

Hello

We have been hacked by [S.W.T], they have put a replacement index page up for catalog (I have removed that)and admin and god knows what else?

Have I left out some security procedures?

Any help appreciated.

london tshirt dot com/upload/admin/

What version are you running? It could be your host got hacked

v1.4.9.1

My host were very quick to respond and have restored files from backup. They think the files were uploaded via ftp. I have changed login details and I am scanning computer.

If they uploaded via FTP, then its not OC but your hosting/username and password. Make sure you have a length of at least 10 characters consisting of lowercase, uppercase and numbers, and NO normal words