Cavalier DSL and Time Capsule as Wireless Router

I recently switched from Verizon DSL to Cavalier DSL in Maryland. I ran the Cavalier modem (Zhone) to a Time Capsule and connected wirelessly. My wireless connection has been very slow (less than that of dial-up), and recently stopped working all together. The Airport gets an IP address and shows to be connected, but the computer is continuously searching for a connection. Note, I also use a PC laptop on the same wireless network, and it is having the same problems. When I am hardwire connected (either through the model or Time Capsule), I get an internet connection with fairly decent speeds.

I also tried a Linksys wireless access point instead of the Time Capsule, and I found the same problems (could get good signal and IP address, but no internet).

Do I have a problem with my time capsule? Any suggestions?