How to port forward with extended router?

I have a Rogers modem running my Ignite 250u internet. I have that connected to my Airport Extreme, giving WiFi to my house. In my room, however, I don''t get a very good signal, so I have an Airport Express set up to extend the network and give my PC a connection. The problem is, I can't seem to figure out how to port forward so that it works for my extended WiFi as well. My extension router is set to bridge mode. Any help?