You are using WiFi, and WiFi have different limits depending on what your router and wifi card are capable of.
The following will take in mind that you will use consumer-grade hardware in a house environment where conditions are optimal (not much interference from signal degration through objects)
2.4Ghz band is limited to about 40mbps in optimal conditions, where 5Ghz can reach 120mbps if all devices support 802.11ac (unlikely). If you can use 5Ghz band it is preferable, but it would be faster to connect the laptop through cable to the router temprarily so you will reach a speed of 100mbps or 1000mbps depending on what is supported on the router and modem and the cable that is used.
EDIT: it seems from other reactions and comments that you need it to be wifi, not using a cable. You may want to edit your post to include that information...
Anyway, your laptop supports the 5Ghz band: 802.11a which will get you a faster speed, but your modem/router does not. Adding an accesspoint (AP for short) that supports the 5ghz band will improve your overall wifi speeds, but keep in mind, that one of the downsides of using the 5Ghz band is, that because the frequency is so much higher, the signal degrades much easier, meaning you won't be able to get a good reception if the AP is in one room, and you are in the other.
So get an AP and place it closest to the position you are going to sit most of your time. If there are 2 locations and they are in separate rooms, get 2 AP's. If you sit on multiple locations in one room, see if there's a spot near the wall that has free range to all these locations, and place the AP there. You will need to bring a LAN cable to the AP though, and power as well, but once they're in place, they don't need to move.
It still won't be as fast as using a LAN cable, but it will be faster than what you have now. If the increase in speed is really worth spending so much money on, I don't know. Depends on how much money you are willing to make it a bit more speedy.