That can be done, bridge the two interfaces on your pc OS, put the ethernet port that c onnects to the fonera with static IP (for example 192.168.10.2) and the fonera also with fixed IP (ex 192.168.10.1), don't forget to put your school network DNS server IP on the fonera WAN config.
In your Network Connections highlight the Ethernet card that currently has internet IE the one thats connected the the college LAN and then highlight the second Ethernet card that has a ethernet cable connected to the La Fonera. Selecting both icon, right click and “add to bridge”.
Reboot your La Fonera and you should an internet ip from your PC. If that doesnt work then do what was said before and set the second Ethernet cards IP manually.
To receive an IP from the bridgin PC, it neeed DHCP, or the college LAN connected to the other ethernet port have to give out more IP addresses from the DHCP. Because it is a LaAN this should not be a problem, but if it were a ISP this could be a problem cause many ISPs only give out one public IP.
If you set the Fonera IP manually, you most note that this will only work if the college is a LAN with private adresses and not directly connected to the Internet.
And the above information is a little bit wrong, when you bridge two ethernet interfaces on your PC ther ewill be created a new "interface", the bridge. This will be required to have DHCP or manual IP, and not the specific individual ethernet cards.They should be left alone.
If your connected directly to a public network, like ISP or College with public IPs, you will maybe need to run NAT on your PC. This could be done ie with ICS on Windows machines, or IP tables and likewise on Linux/Unix.
