Yep, the advice I've been given is that you really haven't/can't do anything to hurt the other person or carry offensive weapons. You can however make use of everyday things around the home, or your person and you can defend your property too.
The other thing to think about is this - if a robber targets us because he thinks we might not use the police, how likely is he to go to the police himself if you do go over the top?
What's he going to say "Excuse me I wish to report an attack", "oh and what were you doing at the time?", "Err I was robbing a prostitute".
Not going to look very good.