I think that you would need to buy a separate print server.
There are a few routers out there that act as print servers and switches but do not incorporate an ADSL modem.
If you do not want a large box on your desk for the print server, try going to Dabs.com (click here) and type in the search box "PS101" (without the "").
It is a small print server from Netgear that plugs into the back of your printer. However, it is for a parallel port so if your printer is only USB and does not have a parallel port then it will not work.
Hope this helps