The simple answer is that if you're using lynx to surf the web, I don't think you're going to have any issues getting the bandwith you need - even without dividing the bandwidth.

The slightly more complicated answer is to look at the iproute2 package. The iproute2 package has several networking functions that may assist you in dividing up traffic fairly.

Edit: I did a little additional looking and found an entire howto on what you're trying to do. The squid section may not be useful to you, but the section on cbq and iproute2 looks promising:

http://www.linuxdocs.org/HOWTOs/Band...WTO/index.html

This advanced routing howto looks promising too:

http://en.tldp.org/HOWTO/Adv-Routing-HOWTO/