Hello and problem!

I ran the anonymous test and got some frightening news! The IP address that came back is NOT mine! It says my computer is connecting to the internet in Lowell, MA and the phone trace comes back with the wrong area code! The internet access and area code belong to my ex-boyfriend. He has an User account on my computer that I can't access (not yet anyway!) and it's his IP address and area code that came back for my computer which tells me he has loaded spyware or something onto my computer! What can I do about this? I have a MAC if that makes a difference. He is also able to track me through my cell phone too, but of course, denies everything! I am at my witts end with this guy and taking legal action against him is something I would definately do but I need proof of what he is doing and I need to stop him.