Mitsubishi - Mirage :: Judder / Shimmy When Braking At Low Speeds

I have a 2000 Mitsubishi Mirage. I've been having issues with judder. I first mentioned it to a mechanic late last spring, but they said the rotors and pads were fine, so I let it be, and the judder got gradually worse, until I brought it in again a couple weeks ago and got new front rotors (the rotors were warped at that point, and barely within spec). But as I left the mechanic's, I realized that the judder had not gone away, it had just changed, and become more pronounced. (Yes, I should have gone right back in to the mechanic, but I was peeved that the problem was still there, and sleep deprived from working 3rd shift.)

The judder is most noticeable when I am stopping in town. The car behaves as if I'm stomping on the brake repeatedly; the brakes are grabbing and releasing, grabbing and releasing. Until the past week, this has meant that my head bobs front and back a bit as I stop. In the past week though, it feels like there is a tiny bit of side-to-side movement developing, too. The steering wheel does not shake, and I can't feel anything unusual in the pedal.(Also, if it matters, the tires were rotated about a week before the rotors were replaced.)

What could the issue be here? Should I take it back to the shop and ask them to undo and redo the lug nuts by hand, since I've read that overtightening, or tightening in the wrong order, could be an issue? Should I ask them if they test run-out when they install rotors? Should I go to a different mechanic? The mechanic I went to is a local large operation with a decent reputation, but... I've gotten some conflicting information from them, depending on who I talk to. Also, should the pads have been replaced along with the rotors? They're at around 70%.