WiFi – Apple Airport Time Capsule with Airport Express

I have already connected and set up an Apple Airport Express and connected to the WLAN.

Recently I bought Apple Time Capsule, which comes with the router. I wonder what options I have.

  1. Disconnect the Express and Setup time capsules as the primary WLAN

  2. Extend the existing WLAN (Apple Airport Express) with this time capsule (not sure if this is possible) and use the capsule only as a backup for files.

Is the router in the time capsule better than the Airport Express?

Please note that I live in a studio so I have no reach.