discouraged - quackgrass

Moved into a home this January where the lawn has been seriously neglected for at least 5 years.  Weeds have been allowed to grow as tall as 4-6 feet in the back yard over the last few years (neighbors tell me).  I have it all, but it is the quackgrass (not crabgrass) that has me really down.

I have been planning all summer to overseed this fall.  I already have the seed and did one area on labor day weekend.  I was working on a second area today and there is so much quackgrass (not crabgrass, but quackgrass).  I have spent all summer chasing the other weeds and did not see this invasion until about a week ago and it seems to have gotten much worse in just one week.  I have been mowing high, watering deep, using alfalfa pellets and cracked corn. . . There has been a huge change in the worm population over the summer. . . so some things are improving.  BUT, if I overseed now, I think I am just going to end up with a quackgrass lawn anyway. 

So can anyone advise how to defeat quackgrass?  What cultural practices will help the bluegrass-fescue and put the quackgrass at a disadvantage?
 

Helen Atthowe has a market garden, with each row of veggies separated by a 3' wide clover lawn. She had quackgrass early on.

In her youtube video series, she reports that frequent mowing, sufficient irrigation, and yearly over-seeding with clover caused "scavenger" plants to out-compete the quackgrass. The champion scavenger in her case was common mallow, but I understand bluegrass is a heavy feeder, as well. It's possible that another turf grass would be better yet at supporting decomposition microbes, in which case you might include such a grass in your seed mix, perhaps adjusting conditions in the favor of bluegrass after the quackgrass is under control.