WAP AC1200

In my home I use two iphones, three wireless pcs, one ethernet pc and a smart tv (all in different rooms). Just recently I purchased the AC1200 WAP.  My cable system provides a router and WAP but in my estimation the WAP alone is inadequate.  The total square footage for my home is 2800 sq.ft. 

I am using the 1000mbps band width which the provider says is adequate.  However, on two or three devices I have to re-connect a pc or tv each time I turn them on.  When connecting the AC1200 do I come directly out of the router into a switch that I have and use for one ethernet pc?  Or do I just replace the provider's unit with the AC1200?

Also, would it be wise to place the WAP in the attic which would allow me to cover the entire house unobstructed?

John