Get a better card perhaps?
A lot of the lower end laptops (and tablets) come with single stream 802.11 b/g/n cards - and getting wide channels these days is not likely...
In good conditions, one can expect to get around 35Mb/Sec throughput - see below:
$ iperf3 -c 192.168.1.20 -Z
Connecting to host 192.168.1.20, port 5201
[ 4] local 192.168.1.140 port 52204 connected to 192.168.1.20 port 5201
[ ID] Interval Transfer Bandwidth Retr Cwnd
[ 4] 0.00-1.00 sec 4.38 MBytes 36.7 Mbits/sec 0 110 KBytes
[ 4] 1.00-2.00 sec 4.14 MBytes 34.8 Mbits/sec 0 124 KBytes
[ 4] 2.00-3.00 sec 4.71 MBytes 39.5 Mbits/sec 0 132 KBytes
[ 4] 3.00-4.00 sec 4.22 MBytes 35.4 Mbits/sec 0 132 KBytes
[ 4] 4.00-5.00 sec 3.37 MBytes 28.3 Mbits/sec 0 132 KBytes
[ 4] 5.00-6.00 sec 3.71 MBytes 31.2 Mbits/sec 0 132 KBytes
[ 4] 6.00-7.00 sec 4.25 MBytes 35.7 Mbits/sec 0 197 KBytes
[ 4] 7.00-8.00 sec 4.46 MBytes 37.4 Mbits/sec 0 197 KBytes
[ 4] 8.00-9.00 sec 3.97 MBytes 33.3 Mbits/sec 0 197 KBytes
[ 4] 9.00-10.00 sec 4.46 MBytes 37.4 Mbits/sec 0 310 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth Retr
[ 4] 0.00-10.00 sec 41.7 MBytes 35.0 Mbits/sec 0 sender
[ 4] 0.00-10.00 sec 41.3 MBytes 34.7 Mbits/sec receiver