If you occasionally had the wobble before the new tires, and if the new tires are larger than the previous tires, it is likely that you have a worn or loose steering component causing the wobble and the larger tires are accentuating the problem.

Get under the front end and inspect all of the steering components for wear. Jack the front wheels up off the ground, and try moving the wheels front-to-back and top-to-bottom, checking for worn bearings in the steering knuckles. Put the wheels back on the ground. While you are under the front end, have a buddy move the steering wheel back and forth (just taking up the slack each way). While he's doing that, you look at the steering components to see what is causing the looseness.

Lastly, in order to eliminate the possibiity of a bad tire balance job, swap the front and rear tires, and then test drive it to see if the problem increases, decreases, or stays the same.