Create the file 'wpa_supplicant.conf'...

$ sudo nano /etc/wpa_supplicant.conf

Put the following in ti:

network={
         ssid="your_wifi_name"
         psk="your_wifi_password"
}

Save, exit 'nano' and run 'ip a' to get your wlan interface name. In my case, is 'wlp2s0'. So, you can run...

$ sudo ip link set wlp2s0 down
$ sudo ip link set wlp2s0 up
$ sudo wpa_supplicant -B -i wlp2s0 -c /etc/wpa_supplicant.conf -Dnl80211,wext
$ dhclient wlp2s0

Should work... maybe... :)

After a reboot, just run:

$ sudo wpa_supplicant -B -i wlp2s0 -c /etc/wpa_supplicant.conf -Dnl80211,wext
$ dhclient wlp2s0