Need Router for +- 100IP

Hello,

I'm a french customer. I installed a network for the small entreprise for which I work (Modem-Router => Switch managable => 15 Wifi AP).

The modem-router of the provider isn't able to manage more than 15-20 IP simultaneously (I think it's the problem).

We need a more powerfull router to manage maximum 100IP simultaneously. 

Can you please advise me ?

Thank you,

Jeff