Also get me the model # of your uVerse modem/router. Changing channels would probably help, but not sure yet.
Another test if you are a night owl - run the test in the middle of the night. There is likely less wireless traffic/interference going on.
TL;DR - the overall problem w/ wireless is competing for "air time". Even though you are on different SSID's (wireless networks), those are just logical, not "physical" networks. You are competing with other wireless networks (and any other devices using the 2.4 or 5ghz spectrum) to transmit data. When there is a crap ton of those devices on the same spectrum, it's going to cause problems.
Distance/range is another problem too which seems evident based on you get better speeds when you are closer to your router. You could try repositioning it, or running a network cable down through the wall somewhere and relocate your router to wherever you spend the most time at.