From my little knowledge of computers, I'd assume he wouldn't be able to track a single IP - a DDOS uses many different computers (a botnet).
Sorry for you, OP. I can't see anyone doing anything to you.
Although the attack uses many computers, some ROUTERS dont give different IPs out for the different computers in your house. Some just use one. But for those who don't, either way, theres an easy solution to this problem.
Step One, find out the IP for ONE of the inbound packets.
Step Two, find out the ISP.
Step Three, contact the ISP, sending proof of the attack and logs, requesting they disable this person's ability to use the internet.
Step Three (IF ITS COMCAST), Realize you're screwed when you find out Comcast's costumer service rating.
I don't know if this would really help but its worth a shot.