My MBA 2012 had it's display changed now the wifi reaches about 15 ft before there is a severe drop off in speed

About two weeks ago my 2012 MBA has a thin strip of Plastic hanging from the display so we brought it into the Mac store to have it fixed. Once the computer was brought home the wifi no longer could be used in the kitchen (the router is in the living room about 30 ft away).

The mac store to their credit tried a lengthy series of diagnostics, but nothing worked. They will not however speak about the hardware replacement of the wifi antenna in the display. I am now the proud owner of a shiney new Broadcom 802.11ac antenna.

Each time I go back to the mac store (4th time now) they claim environmental issues or firmware upgrades to my TC. However there is only other network in range that is using 5Ghz and their channel is different. Also we brought it into my wife's office and the same exact issue happened moving away from her office's router, whereas her work MBP worked fine next to it. Additonally, I don't allow for automatic update so I would now if the TC had an uppate.

When the MBA is next to my router it produces 31 down/5 up. When it is in the kitchen: .05 down/.1 up A very similar drop off happens in the office.

Has anyone else experienced the drop off? Does anyone have a solution, it is driving me bonkers since we can't use the computer in the room we primarily hang out in.