First I’d ask why you want to participate more in ALA? Is there a particular interest or cause you’re interested in? What role do you want to play? Midwinter is generally more business meetings that programming events so it might not be the best choice for general attendance. Annual is full of great programs and events that are open to everyone. If you’re looking to get involved check out the MidWinter schedule, it’s still up http://alamw12.scheduler.ala.org/sessions There are a couple of things that come up related directly to support staff issues
There is a Library Support Staff Interests Round Table too. and there are plenty of things for School librarians that you would be welcome at!
Hope that helps.