Urgent: Working authorizaiton

F-1 only one semester, now there is a job offer, but they don't sponsor H1-B, (even offer, H1-B already runs out). I was told by ISO that I am not eligible for CPT because I enrolled as a full time graduate student only for one semester! But I did enrolled part time before for three semesters. Employer is waiting for my reply, Any suggestions? Any other options? Thanks!!!!!!!