Default [Q] LG G pro 3G issue.


Hi guys, when you have time would you throw an eye on this thread.Merry Christmas to everyone, how are you?

I just bought recently unlocked AT&T made in Korea LG optimus G pro e980
The kernel is of AT&T because when i start the phone i see the logo of AT&T mobile.

I am on Walmart Family mobile plan they are OVN of T-Mobile. I am on unlimited text,data,talk plan, it is included 2 GB of 3G data.
The android version of the phone is 4.1.2, baseband version APQ8064,MDM9X15m Kernel 3.4.0, build number JZO54K,software version E98010k

My APN settings are as follows, i tried the one from FAQ of family mobile too, but i still couldn't have 3G coverage.
Name: T-Mobile US
Port: 8080
Username: (leave this blank)
Password: (leave this blank)
Server: (leave this blank)
MMS Proxy:
MMS Port: 8080
MMS Protocol: WAP 2.0
MCC: 310
MNC: 260
APN Type: (leave this blank)

On the top corner of the screen above the network coverage stays the letter "E" (EDGE) and the internet is very slow!
I've seen they are many AT&T brand applications are installed on the device like: at&t drive mode, at&t Locker, at&t Navigator e.t.c.

Please guys what you would suggest me what i have to do. Do i need to root, to unlock the boot loader, or to change the base bands to get the 3G coverage or what? I would be thankful if you answer me with links or step by step what i have to do, because i am newbie in this area, i have experience in desktop pc, laptops, some software and hardware knowledge, i am mint in smartphones.
I live now in Bryans Road, Maryland this area is 3G covered i already checked.
When i search on networks in the phone i also see signals from AT&T antennas like AT&T RAT:14,3,2 and three for Family mobile.
Thank you. Mr. Stark recommend me to change the preferred network to 3G or LTE in settings, i am still trying to find where is that in my phone, but can't find it