Problems installing - only one ethernet on modem

Hello,
I am new to Voipo, and am working on installing my Adapter. Last week I switched my internet to be through the cable company and I bought a cable modem that Voipo said would work for Voipo. Anyway, when trying to install today, I realized that I cannot install because my Wireless Modem only has one ethernet, which is being used for my computer that is not wireless. I also have a wireless laptop, which is why I bought a wireless modem. So I cannot plug my adapter into my modem. What do I do? I don't want to have to spend more money, and my number ports on Tuesday, and then I will have no phone service if I cannot get this to work.
Thanks,

Get a cheap 5 port network switch plug the cable modem into it then up to 4 other things into the switch like your computer and the voip device.

Yes, you can get a 5 port switch on amazon for less than $20. I've had good luck with the TrendNet brand.