Yes, children with Asperger's Disorder are often able to establish eye contact, so her ability to establish eye contact would not, in and of itself, rule out that diagnosis. Relative to the medication, diminished social contact is not generally a side effect of psychostimulants. Did she display more advanced social skills prior to taking medication? Has her demeanor changed after she started taking medication? If there is really no change in her baseline state in this regard, you needn't suspect a problem with the medication. In order to enhance social functioning, some form of group treatment is preferable to individual therapy/counseling. Ask about this at school; some schools offer social skills groups or social problem-solving groups. Also, check with her insurance company about providers in your area who offer groups for children her age. Finally, if she is not enrolled in recreational opportunities with peers, arrange for something. The activity itself isn't as important as the need to interact with peers.
You might ask the doctor if the med is impacting her abitlity to be social. I have read some literature stating that some ADHD meds, Ritalin for example, are not good for certain kids with ADHD because impacts their ability to socialize. I believe that there are other medications for ADHD that are better at controlling ADHD and also insure that the child is still able to socialize. I am not sure if Dr. Kennedy has an opinion on which ADHD medications improve peer relations or minimize the symptoms of hyper focusing that impact their ability to make friends. A social skills class will also help her, most of all if you suspect AS. Good luck.