I know it's a bit late, but maybe usefull for other people. I think that if you want you can use your only one ethernet notebook as router simulating two nics this way (on Linux. If you are on Windows not sure if you can):
Get a 4 port USB hub as well, although I'll say this, there is a CPU overhead that may impact your overal performance but...if you have 1 free USB port (as a quick search has indicated for your model)it may be do-able. I have found that a USB modem that we have connected to an old PC I think its a 386 with something like 128Mb of RAM really struggles every now and then with all the processes running for win XP so you may get lucky and have a smoother experience as a just a router
Come on peeps...
KINAMAX NT-USB20 USB 2.0 to RJ45 Fast Ethernet 10/100 Base-T Network Adapter - Retail