wireless - Wifi extremely slow on ubuntu 16.04, tried almost everything and still not working properly

I have a Dell Latitude E6400 laptop and my wifi is extremely slow, it takes ages to load some pages not to speak about videos. All other devices on the same wifi have proper internet speed

This is the output for

sudo lshw -C network

*-network
description: Wireless interface
physical id: 2
logical name: wlan0
serial: 00:23:4d:b3:4d:ba
capabilities: ethernet physical wireless
configuration: broadcast=yes driver=b43 driverversion=4.10.0-30-generic firmware=666.2 ip=192.168.0.31
link=yes multicast=yes wireless=IEEE 802.11

Output for iwconfig:

enp0s25 no wireless extensions.

wlan0 IEEE 802.11 ESSID:"UPC6750748"
Mode:Managed Frequency:2.462 GHz Access Point: FC:B4:E6:8D:C2:D0
Bit Rate=54 Mb/s Tx-Power=20 dBm
Retry short limit:7 RTS thr:off Fragment thr:off
Power Management:off
Link Quality=59/70 Signal level=-51 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:229 Invalid misc:320 Missed beacon:0

lo no wireless extensions.

Output for lsusb:

Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 008
Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 007 Device
001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 006 Device 001: ID
1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 001: ID
1d6b:0002 Linux Foundation 2.0 root hub Bus 005 Device 002: ID
0a5c:5800 Broadcom Corp. BCM5880 Secure Applications Processor Bus 005
Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 004 Device
001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 003 Device 001: ID
1d6b:0001 Linux Foundation 1.1 root hub

rfkill list all

0: phy0: Wireless LAN Soft blocked: no Hard blocked: no 1: dell-wifi: Wireless LAN Soft blocked: no Hard blocked: no

Please help, I tried loads of tips from the internet, but still no improvement.

I also read a tip about using wicd but it is not showing my wireless connection....

Output for lspci -knn | grep Net -A3

00:19.0 Ethernet controller [0200]: Intel Corporation 82567LM Gigabit
Network Connection [8086:10f5] (rev 03) Subsystem: Dell 82567LM
Gigabit Network Connection [1028:0233] Kernel driver in use: e1000e
Kernel modules: e1000e 00:1a.0 USB controller [0c03]: Intel
Corporation 82801I (ICH9 Family) USB UHCI Controller #4 [8086:2937]
(rev 03)
-- 0c:00.0 Network controller [0280]: Broadcom Corporation BCM4322 802.11a/b/g/n Wireless LAN Controller [14e4:432b] (rev 01) Subsystem: Dell Wireless 1510 Wireless-N WLAN Mini-Card [1028:000d] Kernel
driver in use: b43-pci-bridge Kernel modules: ssb