Well, is it the Ring, but speaking to Frodo then?
My treachery leads to your great deeds - because of the Ring's treachery to Isildur (or maybe even Gollum), Frodo eventually gained the Ring and therefore could, well, make great deeds
I've broken your family, then protected you from harm - Bilbo had to leave to Rivendell, Frodo was then protected (sometimes) by the Ring
Because of me you safely escaped, because of me you had to - Meaning he left the Shire (he had to)
My protection lasts only tonight - oh, I now noticed you said it refers to one literal night. Well then, it could be on Weathertop. Of course, the above does not necessary have to be said on Weathertop, the Ring could tell it to Frodo anytime. Is it important? I mean, is the speech above bound only to that specific night? Couldn't the subject tell it any other night? If not, my guess is probably wrong.