Wireless problem on inspiron n5520

Hi, I just got dell inspirion n5520. After clean OS install (win7 64bit), my wireless has random crashes. Sometimes it can last for hours, sometimes it crashes 5 times in 2 mins. When I was installing drivers I'm pretty sure i didn't follow correct order. I have read several topics, and now I'm prepared to do a clean OS installation one more time, and install drivers in correct order. 

These are my questions:

1. I was using this page as reference to driver installation order : http://support.dell.com/support/topics/global.aspx/support/kcs/document?c=us&docid=268873&doclang=en&l=en&s=gen&cs=   

Notebook System Software  seems to be quite important, but when i typed my service tag it didn't appear in the list of drivers for my laptop (I can provide screenshot if necessary). 

2. On my list there are "duplicate" drivers, A00 and A01, I'm not sure which one should I install, or maybe both.

My plan was to do a fresh OS install, and then install drivers in this order:

1. chipset drivers: ( there are 4 of them listed under chipset ) INTEL Intel USB3.0; INTEL Intel Panther Point HM77 Chipset; INTEL Intel Management Engine Interface; REALTEK SEMICONDUCTOR CORP Realtek RTS5179 Card Reader;  

2. intel storage

3. audio /video

4. network (under network are 4 drivers) one is for Ethernet, 3 are for wireless ATHEROS COMMUNICATIONS Dell Wireless 1x1 WLAN 802.11b/g/n (2.4GHz), Bluetooth v4.0+HS; and two are Dell Dell Wireless 1x1 WLAN 802.11b/g/n (2.4GHz), Bluetooth v4.0+HS  with only difference in A00 and A01.

What should I install, please help. 

system info: 

OS Name:                   Microsoft Windows 7 Professional 
OS Version:                6.1.7601 Service Pack 1 Build 7601
OS Manufacturer:           Microsoft Corporation
Original Install Date:     13.9.2012., 20:08:08
System Boot Time:          30.9.2012., 15:56:24
System Manufacturer:       Dell Inc.
System Model:              Inspiron 5520
System Type:               x64-based PC
Processor(s):              1 Processor(s) Installed.
BIOS Version:              Dell Inc. A07, 17.5.2012.
System Locale:             hr;Croatian
Input Locale:              hr;Croatian
Time Zone:                 (UTC+01:00) Sarajevo, Skopje, Warsaw, Zagreb

Windows IP Configuration

   Host Name . . . . . . . . . . . . : 5o5
   Primary Dns Suffix  . . . . . . . : 
   Node Type . . . . . . . . . . . . : Hybrid
   IP Routing Enabled. . . . . . . . : No
   WINS Proxy Enabled. . . . . . . . : No
   DNS Suffix Search List. . . . . . : sx76x.gigaset.net

Wireless LAN adapter Wireless Network Connection:

   Connection-specific DNS Suffix  . : sx76x.gigaset.net
   Description . . . . . . . . . . . : Dell Wireless 1704 802.11b/g/n (2.4GHz)
   Physical Address. . . . . . . . . : C0-18-85-BE-FC-1F
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::ec08:ca28:5681:bb2e%15(Preferred) 
   IPv4 Address. . . . . . . . . . . : 192.168.1.242(Preferred) 
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : 30. rujna 2012. 16:03:21
   Lease Expires . . . . . . . . . . : 30. rujna 2012. 17:18:21
   Default Gateway . . . . . . . . . : 192.168.1.1
   DHCP Server . . . . . . . . . . . : 192.168.1.1
   DHCPv6 IAID . . . . . . . . . . . : 398465157
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-17-E3-E9-99-C0-18-85-BE-FC-1F
   DNS Servers . . . . . . . . . . . : 192.168.1.1
   NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Local Area Connection 2:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . : 
   Description . . . . . . . . . . . : Realtek PCIe FE Family Controller
   Physical Address. . . . . . . . . : D4-BE-D9-4E-98-A9
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter isatap.sx76x.gigaset.net:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . : sx76x.gigaset.net
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter isatap.{089429CA-895F-457B-AD39-CEEC4CCF8E92}:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . : 
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter #2
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Teredo Tunneling Pseudo-Interface:

   Connection-specific DNS Suffix  . : 
   Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv6 Address. . . . . . . . . . . : 2001:0:5ef5:79fb:10d6:12b:3f57:fe0d(Preferred) 
   Link-local IPv6 Address . . . . . : fe80::10d6:12b:3f57:fe0d%13(Preferred) 
   Default Gateway . . . . . . . . . : ::
   NetBIOS over Tcpip. . . . . . . . : Disabled