Question : How to restrict incoming RDP on a Windows XP PC from a particular WAN IP  ?

I have an work PC with RDP enabled on this WIndows XP PC.

The listening port is 3389

If I wanted to access this work PC from home , I need to forward port 3389 on our
office firewall to my Work PC LAN IP.

Now can I configure my work PC in such a way that the incoming 3389 can only be listened
from a particular WAN IP (my home cable internet IP address -- which is STATIC IP ).  

I wanted to do this configuration on my Windows XP work PC, as I cannot do the setup on my
network firewall (its not that intelligent- as its a basic firewall which has only port forwarding option,but does not allow us to create a rule )

Answer : How to restrict incoming RDP on a Windows XP PC from a particular WAN IP  ?

Did you have a look into the XP Firewall? It should be able to allow 3389 for a single IP only.