I vote for puppy classes (although do some research on which one, I don't know if PetSmart is the best choice). The benefits of socializing your dog as early as possible will have immense life-long benefits. Here is a super article on the why/how/who and when of puppy classes:
http://www.dogstardaily.com/training/puppy-classes
I also agree with BMDLuver about the leash corrections. There really is no need in a pup so young. Training should be fun and easy and pleasurable for both of you, if it isn't, you're doing something wrong. Dr. Ian Dunbar has a fabulous site with lots of training info that I highly recommend you read through:
http://www.dogstardaily.com/training
And food treats shouldn't be used as a bribe in the manner that you're describing them, but as a
reward for having performed a behaviour you approve of.
http://www.dogstardaily.com/blogs/wh...al-food-bribes
http://www.dogstardaily.com/training...eward-training
http://www.dogstardaily.com/blogs/wh...t-what-isn039t
http://www.dogstardaily.com/training/food-critics