MR1000 dropping connection to internet constantly

Having issues with my MR1100 wfi router on AT&T service. First issue is it won't recognize my password which has not been changed and is stored on my computer to autoload. So I can not access anything beyond the first screen. Yet at one point it gave me a screen that allowed me to reset my password, I told it no and it input the very same password I have on my computer. 

But that is only the first frustration. Most of my issue is that I cannot maintain a consistent connection to the internet. It keeps dropping it in the middle of downloading.

We have lousy AT&T reception usually 1 and sometime 2 bars. So I am looking at trying to set up a Yagi attenna and whatever else I need to make it work. Our phones at times won't connect inside our home or are so broken up the person on the other end can't understand what we are saying.

So if someone can tell me how to set up the Yagi by bringing in a cable from the outdoor antenna to whatever I need inside I would be greatful. 

I am on a Mac desktop platform but also have laptops and Directv trying to work off the system. Cannot get a good enough signal to use the start over or download or any of the bells and whistles on Directv. 

I can connect by eithernet to my MR1100 but it seems I need something to enhance the reception of the signal from outside and move it inside. If I bring the outside into a router in my attic (we have metal roof but it also has expanded foam under the roof) I am thinking of putting the router in the attic because it will just have 5/8ths inch sheetrock to penetrate to get to the home office or other rooms in the house.