I never had a time capsule, but my short experience with two WL-500W for tests with as a wireless bridge are not that pleasant.
The encrypted wireless throughput was about 40MBit/sec only, slightly above a regular 108MBit Super-G wireless MiniPCI.
A printer connected via a USB to network print server will probably never show its ink levels. You should get a printer with an integrated network interface.
I doubt that the WL-500W will be able to provide a time capsule server.
Additionally, it does provide a 100MBit switch only, but I think, it even will not be able to have enough troughput for that.
If you want to have a small, fast server, you should look for a small device with an Intel Atom processor, an SATA Interface and GBit LAN, running a regular linux distro.