Yes. AP is an Access Point.
It's just an option. If you have a router you like and works for you, and you want to be able to connect utilizing 802.11ac, you could just attach an Access Point with 802.11ac capabilities. Sometimes that is less expensive.
Remember, what is often referred to as a router... is most often more than just a router. I believe your "box" is a modem (communicates with the cable company), a router (routes data to the appropriate computer and handles DHCP), an Access Point (allows you to connect via radio waves or wifi), and also a switch (I think yours has probably 4 places to plug in an ethernet cable.) If you had a "stand alone" access point, it would provide the radio communications/wifi and would connect everything to your network via an ethernet cable between it and your router.
On my network in the office, I have a router, that also has a 4 port switch, but no radio - downstairs. I have an access point upstairs. I happen to have a 5 ft antennae on the roof attached to the access point because I have a wireless bridge/access point located in my shop nearly 1/4 mile away connected to another switch that lets me have internet access there. And it so happens I also have another access point (connected to the switch) located on the other side of the shop which allows me to have wifi at my home which is another 600 ft or so away (Cant pick up a decent signal directly from the big antenna at the office because there is a pond bank, a barn, a cistern house, a storage shed, and some trees between my house and the office.).
Anyhow, I haven't tried to price equipment lately. I'm just suggesting that you look at your options. You don't need to replace everything just to get a different radio signal. You can just get a different radio signal. By the same token, if you want to use 802.11ac and your laptop doesn't have that capability... you might not want to buy a new laptop. You can get a USB wifi adapter that receives 802.11ac for $50 or $60.