Comcast controls the IP. It is dynamic and will change someday. It's not worth discussion past that point. Let's move to what we can write about which is port forwarding.

If your machine is at a specific IP in your LAN you can forward incoming ports to that machine. I will not duplicate web content or what you can do at http://portforward.com/ for free.

No where did you specifically tell what you needed to do so this discussion ends with jelly, nails and the wall. Please be a little more specific as to what you want to do rather than a generic port forward discussion.
Bob

PS. I see a torrent client running. I never help with torrent setups since those are discussed already far and wide.