Here is what I said above:
......
you will need to have.....or be able to borrow for 20 minutes or so.....an older Mac running the Leopard (10.5.x) or Snow Leopard (10.6.x) operating systems, or a PC that has AirPort Utility for Windows installed on the device.
What this means.......
You would need to have an older Mac that was using the older Leopard (10.5.x) or the older Snow Leopard (10.6.x) operating system, or a PC with AirPort Utility for Windows installed on the device.......to be able to configure and administer the older version of the AirPort router. Newer operating systems like El Capitan (10.11.x), Yosemite (10.10.x), Mavericks (10.9.x) and Mountain Lion (10.8.x) do not have a compatible version of AirPort Utility that could be used to administer the older AirPort Express.
If you did not have an older Mac running Leopard or Snow Leopard, or a PC in your possession......but you could borrow one from a friend for the 15-20 minutes that it might take to set up the older AirPort router.....then that might be an option for you.
Apple has classified the older AirPort Express that you have as officially "obsolete". That means that Apple will not offer any kind of support for the product, even if you are willing to pay them. But, if you have access to a Mac using an older operating system or a PC.......and assuming that the AirPort Express is still functioning correctly........(It should have failed 4-5 years ago)......you might be able to make it go a bit longer.