Currently there is no graphical dialog for managing the IP-filters. But you can still modify the ipfilter configuration file at ~/.torium/ipfilters.
To filter out an IP-range, seperate the starting address and the ending address with a dash like this:
213.13.44.3-213.13.44.7/100
The /100 at the end of the line tells Torium to block the IP-addresses within the given range.