Browsing network shares from behind a router.

I'm in a dorm. In my room I have a desktop and an ancient laptop. Since the Resnet only assigns us one IP, I use a router to connect both PC and laptop to the internet. Swapping off the router is not simple because of a buggy as shit activation process the ResNet service uses to bind to a MAC.

Is there a way to browse network shares even though I'm on my private subnet? I'm not in the mood to violate my universities AUP, so no uber-fast IP range share scanner type progs.

>19
Another NIC = another 10 - 25 dollars, more for a Wifi card.
Setting up 2 NIC's, AdHoc, and ICS = time.
If my main computer goes down, no Wifi for the laptop. That's no good.

How is this a better setup than just using a router?

My question is how to see shares from behind a router. If you don't know how and I say I won't remove the rotuer than don't fucking tell me to remove the router.