The only other options I can think of...
1. Use a PC with a HomePNA card, and a normal network card to do Internet Connection Sharing
2. Connect a wireless access point to the router -- Expensive route because you'd have to buy a WAP and a wireless PCMCIA card so not really a cheaper alternative.
---- Edit ----
Note: Just because your DSL comes in through the phone does NOT mean your whole house will be wired for internet through the phone lines
You'll need a DSL Modem to connect to the phone line, and then a HomePNA router to wire the house through phone lines
Don't take offense if this is what you've done, just being caution to make sure people understand what's happening