DHCP and Cox Cable

I am hoping you can help me with a small problem with my Cox service.

I have a web server behind my firewall and I used to be able to access it
because I had a fixed IP. I switched over to the new Cox service, and Cox is
changing my IP address. Is there anyway to get to my web server through my
firewall on a consistent basis? I use the server for projects and need to
access it from the road. I am not a networking expert, so I am not sure how
to do this.

I can't use the web pages provided by Cox because I have servlets running
with JSP, EJB, etc. on the server.

Thanks!

Mark Phillips