I could be mistaking but this is not what the OP is looking for.
The OP has a setup like this:
WiFi Network -- Owned Router -- | University Network (unowned) | -- Owned router -- PC
And he want's to have communication between the PC and the WiFi Network. @Darth Beeius is that right?
This would require a few things.
First of all both of your routers must have a fixed IP address in the university network.
Your univerity shouldn't have some firewall in place which blocks packets which are unknown to it.
If so you want to build a GRE tunnel between the two routers. You probably also want to enable a routing protocol (like OSPF) to advertise the routes in both networks (depending on the setup you might not need this).
I haven't working with dd-wrt but this tutorial seems to be what you need: https://www.dd-wrt.com/wiki/index.php/EoIP_Routing
