1gb internet and Router/Modem - eviltoast

Hi Guys,

I recently upgrade my optimum network to a 1g internet but noticed I only get 600mb download. When I called up optimum they state I cant get 1gbp download speed because I have a router and modem and I’m not connecting directly to my modem. My modem has only one post and that’s why I use a router. Will getting a modem/router all in one fix this issue? If so what modem would you guys recommend that wouldn’t break the bank?