This is very scary, I also agree that this person should be reported and asap. This seems above and beyond the regular creepy guy at the mall, he seems like a full blown stalker. I would also be concerned about him having a plate#, the guy sounds like a freaking whack job. I also don't like the sounds of him hanging in the Target every day for 2 weeks, it sounds like he is scoping for a child to take from a frazzled mom or something. I am speaking from having a crazy freak who really scared me about 8 years ago, the guy would come into the bar I worked at and would do nothing but stare and say weird stuff to me, I always had someone walk me to my car when I'd leave. I told DH about it and then didn't see the guy for awhile. One night he was at a different bar and DH was with me, when we left the crazy dude followed me out, DH stopped to talk to a friend. I jumped in our car and locked the door, and he came up to the car trying to talk to me knocking on the window. DH came unglued and told him if he EVER spoke to me again he would f-ing kill him. I have never heard DH say anything like that ever and I truly believe he would have.
*side note* this guy had been a counselor at our local HS and had been run out of town for objectionable behavior toward female students, I found this all out after my experiences. He is still in education, freaky.
Just please contact the police with a description, this guy sounds very dangerous. You did awesome with the situation though.