You might want to get in the habit of doing this so you don’t have to restart rtorrent all the time.
Ctrl + x, import=~/.rtorrent.rc
If you are only adding a few lines, you can just Ctrl + x and paste/enter them for them to be loaded.
Thanks,
http://rakshasa.no/pipermail/libtorrent-devel/2008-January/001476.html