I have aspergers and give the impression that im smart when I talk but in fact my iq is lower than average?

People with Aspergers need to be within the "normal" or non intellectually disabled range. However, this varies from borderline to very superior so you could have Aspergers and be in the "low average" range. Sometimes people with aspergers have particular "islands" of ability so you could be really skilled in being articulate but have an overall IQ in the low average range as IQ scores are made up of lots of different areas though. Don't worry though low average is still within the overall average range and applies to a big section of people.