It only took them 1 day to fix my sewing machine! (and another day for me to go pick it up, and another day for me to finally unpack it.)
Turns out it doesn't wobble because it's missing a foot, it wobbles because of my sway-back table. I forgot to have them look at the little screw that holds the foot on though. It doesn't stay tight. Next time--it's not a huge problem.
Here are some pictures: