For me personally I have a Netgear Hub, and two Nic cards, What you need to do is get a Cat5 whatever length you need, and it needs to have a crossover bit in the middle of it. You can be sure of it is it crossovered by looking at the head of the RJ45 connectors, they should be exactly the same. You need software to allow for mutlti users to share 1 connection, or set it up manually if youa re a pro, But I personally am not sure how to do it. Use the better card for the DSL, and the not so good one for the LAN. With a better card you should get a better connection, or clearer connection. The LAN does not really matter for speed, because you will only be sending limited data across them.
Hope this helped you out.
Albert.