Can airport time capsule be used for something else besides a router

...could i use my time capsule as a second wireless router on like my first floor and/or as an external back up.

Potentially, yes, for both.

To be used as a second wireless router, your Time Capsule (TC) would need to be connected back to your new Netgear router by Ethernet. The two of the would be the foundation of a roaming type network. You will NOT be able to extend the Netgear with the TC using a wireless connection between them.

If you just want to use the TC for Time Machine backups, you can connect it directly to one of the LAN ports on the Netgear, and then, reconfigure the TC as a bridge and disable its wireless radios. If you need help with how to do so, let us know.

Ok, then the key to success, will be the following configuration for your TC:

• Connect a Ethernet patch cable between one of the LAN/Ethernet ports on the Netgear to the WAN (circle-of-dots) ports on the TC.
• Reconfigure the TC for:
  • Bridge Mode - AirPort Utility > Select the TC > Edit > Network tab > Router Mode = Off (Bridge Mode) > Update
  • Disable the wireless radios - AirPort Utility > Select the TC > Edit > Wireless tab > Network Mode = Off > Update

One additional suggestion for the TC, since you will mainly be using it for Time Machine backups and that is to assign it a static private IP address. This will allow network clients to find it more easily.

To do so: AirPort Utility > Select the TC > Edit > Internet tab > Connect Using = Static.

Use an IP address outside of the DHCP scope of the Netgear router. That is, if the DHCP scope is set to (for example): 192.168.1.2 thru 192.168.1.200, set the TC to: 192.168.1.201. For the other addresses enter the one appropriate for your network.

Which model Time Capsule? If it is the tower model AC wireless just say tower. Earlier pizza box ones look on the base for the model number.. A1409 for example is Gen4.

Do you need to get signal upstairs then even if you don't want to use ethernet you can get a pair of powerline adapters and see if they give you reasonable speed. There is no way to know without testing.. so buy from a store with good return policy. I recommend one of the kits with AV1000 or above. If it works they can be very good.. in being fairly stable and reliable.

There are two ways to use it otherwise.. plug it directly to the Netgear router downstairs by ethernet short patch cable. Turn off the wireless and configure it in bridge .. then it should be available as storage to your computers connected via the Netgear. This can be unreliable though so if you do it this way ask for details.

Or you can plug it by ethernet directly into a computer upstairs. This setup is a bit tricky so again say this is what you want to do.. but I suspect in neither role are you going to find it great. I would actually say it is better to sell it for a USB drive and plug that into the Netgear and use that for storage. Some Netgear even support Time Machine although I have never tested it.