Career advice needed - temp to perm situation?

Background: I’ve been working in the payroll field for the last 18 months, I was unemployed for a year from Oct 2010-Oct 2011. In my first job back from unemployment I temped for two months before being offered a permanent position, I stayed there two more months before being offered a temporary position for a lot more money at my current job with a very large empoyer in NYC (starting March 2012). I am one of 7 temps brought into this department in March.

I am still working at the temp job, and they are posting permanent positions for our department. Three weeks ago they posted 3 permenant positions for our dept (same job function), I got an email from the HR department Friday (none of the others temps have contacted yet). The positions are asking for a minimum of 3 yrs payroll experience, the HR person emailed me my resume shows 18months experience, she is asking me to verify my 3 yrs experience.

What should I say?

I applied for the positions twice, there were screening questions during the online application process and I answered them first that I did not have 3 yrs exp. and then the second time saying yes I did have 3 yrs exp. My resume is accurate.

I stay late, come in before the managers do on days I dont take my son to school, I am the only temp they are training to run the payroll, I get special training/assignments, I’m the only temp they regularly allow to sumbit 40 hrs timecards instead of only the 37.5 the other temps are allowed to submit.

How should I respond to the HR woman?