yes to my knowledge you have to enroll in school, coz if not as a internationa student you would be out of status, and one cant sposnor someone who's illegal. but again, after you get the receipt, depending on the state, if you go and talk to them, and if you've been in that state for 9 months, which i assume u have, they should let you pay instate tuiton fee rather and outta state, but again some school will make you wait for 9 more months after you get the 1485 receipt. but again, you say your employer has filed your papers, but what about labor certification, i 140, and then only comes the 485.