It appears this router comes with two cables included. One for your telephone line connection and one for your computer (an RJ45 patch or straight through cable). It is the RJ45 cable that you need two of; one for each computer.
Certainly, the equipment will allow you to share your ADSL connection, but AOL have some strange (non-standard) protocols and there have been reports in the past, that AOL can be a problem. Whether this is still the case, I don't know.