You are not going to get any money from this via a lawsuit. You are going to shell out decent cash to pay the attorney and chances of you getting any money from the person using your images is slim to none.
Best thing you can do is shoot an email over to POF and ask for the images to be taken down. You can always contact the affiliate network and tell them to relay the message to the pub that the images cannot be used.
You are better off going through the 'free' processes of getting the images taken down. You are wishful thinking if you think you can sue and actually collect money. Unless it's a huge company that is using your images it's not worth your time.
Brian