fiber internet

Hello all interested, i have recently "upgraded" to a fiber internet with AT&T with guaranteed speeds of 1000Mbs up and down. My problems started when I typed AT&T, but the real problem is I am not receiving 1Gb internet speeds. Here is my current status, I am using a PCIE network card that...

I want to use two of my own routers with my AT&T Fiber internet. Basically, i want to use one of them as the main router to use instead of the one provided by AT&T (Motorola NVG589) but i also have a second router which i was thinking of using to get coverage in another part of the house...