Most 141 ground school programs will take longer than 2 months. I'll throw my vote for St. Charles Flying service. Their planes aren't as pretty as Air Associates but they're well maintained and SET is a nice, quiet airport to work out of with plenty of towered airports nearby as well as St. Louis approach. You don't need to pay the premium for a G-1000 and a bunch of crap like that. As a private pilot you should be looking outside.
If you want to do it in two months, you can put in a lot of time on your own studying. On a day that you get rained out you should still meet with your instructor to review the ground school stuff to prep for the written and oral portions of your rating exam. If you do those things, you should be able to get the private in 2-3 months as long as the weather cooperates.