Cannot access my Windows 2003 Server @ work from Home using Desktop Remote

Hi, I have the admin user ID and Passw and i want to access my Windows 2003 server at work from home and when i enter the IP address for the server using Remote Desktop connection at home is giving me this message:

“The Client cannot connect to the remote computer..
Remote connections might not be enable or the computer might be too busy to acept new connections”

If im at work on the netowrk i can connect using my remote desktop but not at home.
Looks like doesnt recognize the IP address or something with the firewall.
Plese help.

thanks,