Is your PS3 connected via your PC, or to a router?
If its via the PC then it might be the virus, if its going direct to a router then I doubt its the virus!
What happens if you reset your router settings, then dis-connect your PC? My guess is that you will get the same results regardless of whether or not your PC is connected.
Are you using bittorrent?? I had a problem where when I used torrent I would get kicked off PSN every 5 minutes or so. As soon as I turn off bittorrent on all my PC's I could log on and play on PSN for hours without any problems!
One theory is that the virus might be using the same ports as the PS3 to transmit data back to whoever made it, so thats why your PS3 is getting booted off.
If you dis-connect your PC from the router or turn it off and you still get the same problem you can rule out the virus being the cause! If that fixes your problem then its probably the virus!
More importantly....why are you busy trying to get your PS3 back online when you have a friggen virus on your PC?!?!?!?!?! FIRST get rid of the virus and be 110% sure its gone!
THEN mess about trying to get the PS3 back online!