slow down there girl...
first of all, how do you know she won't need an IEP ?...my son who's very high-functioning has one, but only had one put in place at the age of 13......
next: screening...primary docs don't usually do these, and it IMO is best to get a screening from someone versed in ASDs...You'll find, though, unfortunately that most docs who do screenings don't take insurance ( at least in my part of the world)...we've had 2 evals done for our son~one was by a psychiatrist that cost $800, the other was by a neuropsych & that cost $1500....
if you can hold out until your child is of school age ( even early intervention age which is , i think, 3 years old), sometimes the school system will pick up the tab of a screening.