If you bought her, she should be in her room all day. Could you tell me what happened when you bought her? Did you get the cutscene returning together at home and showing her the bedroom, and then she disappeared or what?
Let's see... Did you talk to the merchant after your buy her? He says to do it when you are ready after you get her contract, and that's when she is brought to your house, together with you. Maybe you forgot to interact with him.
I understand. I made it this way because I didn't want to "warp" players back to Tarkas if they still had stuff to do in Rahib, but perhaps I should make it automatic, or at least change the text color so that it's more noticeable when he tells you what you need to do.