Time Capsule. Drive is ok, cannot connect through wifi

Yes you can. Since the Time Capsule is an Airport Extreme with an internal hard drive it's relatively easy to convert it into a wireless to wired bridge assuming you already have it set to hook up to the wireless network.

1. Open up Airport Utility and start Manual Setup on your Time Capsule
2. Go to the Internet section
3. Under Internet Connection be sure Connection Sharing is set to Bridge Mode

If bridge mode is turned on it will share the connection and essentially act like a switch.

First, connect one of the Ethernet ports of the 2Wire Gateway to the WAN port of the Time Capsule and turn both devices on, and disable wireless on the 2Wire. Your Time Capsule settings should not be changed from what they were when you had things working with your cable modem. If you've changed them, change them back now.

Then, on the 2Wire Gateway, in the "LAN" section:

1. Enable DMZ for the Time Capsule connection
2. Turn off the firewall for the Time Capsule connection
3. Set the Address Assignment for the Time Capsule connection to "public"
4. Set the WAN IP Mapping for the Time Capsule connection to "Router WAN IP address"

Then cycle power on the Time Capsule. The Time Capsule will now control everything just like it did when it was connected directly to your cable modem. Any wired Ethernet connections you add should be connected to the Time Capsule, not the 2Wire Gateway.

FYI, this works for any router or access point, not just the Time Capsule.