Adding an extra year to my degree?

I'm currently a UL student and was due to go abroad for the next semester, but for medical reasons I've had to cancel. I will be able to take classes in UL instead, but still really want to go on study abroad. Because of the structure of my course, I can't go abroad during another semester. Going to a foreign university when it's not part of an exchange program would be far too expensive. I was just wondering if anyone knows if it would be possible for me to add and extra year to my degree by registering with UL for an extra year (before 4th year), and then going abroad on an exchange?