Replace Cisco box for phone connection

I have a Cisco box SPA112 to connect my telephone to the wired (cable) router. It's at my little holiday home in France. This gives me access to the OVH world through which I can make phone calls. Now I'm replacing the wired router with a wireless one so I will need to replace the Cisco box with an equivalent that attaches to the new wireless router over WiFi. How should I go about that? I find this OVH web site massively confusing so please help me in simple minimally technical language! Thanks