My suggestion

There are several home/small-office wireless routers that can be configred as Wireless Access Points by disabling the NAT of the routers(from $10 to $30 after rebate). You can connect the access point to your old router. This way is:
- cheaper with flexible ( you can place the access point anywhere for better signal, and you would have the access point as a backup router).
- all the connected computers are in same sub-network to get resource sharing easily.