Wierd story
This story sounds like one of the hoaxes we ussually get on emails. There are a couple (if not several) things that don't fit. First of all, there's nothing here to call for self defense. Revenge is what we have here, and since it was planned, it's even worse (there are terms for this in law, but I don't know them in english). Besides, the only way she could get away with the "self-defense" argument is if the man was (the second time) as agressive as the first time (wich, by the way, I doubt, since he was invited) and of course she cant tell anybody that she clearly invited the man, as well as almost thanked him for their first encounter. Also, the story doesn't say clearly when did she kill the guy (right when she saw him, after they had sex, in case they did it, or when?). Finally, is she telling it just like that? that's very odd.
After I started writting I asked my mother about this, because she's a lawyer, and she told me that the case has all the "agravantes" to make this a criminal case and that the woman could be sentenced to up to 30 years (the maximun in DR). The only thing that could get her away is if the Judge find that: 1) the attack left the woman so shocked that she wasn't in control of herself (but really, after one week?) or 2) the rapist was just the lowest of the lowest (this part I didn't understand very well).