Prep Time vs. Student Time

I'm facing one of those personal conflicts I think most teachers struggle with. I'm a 3rd year teacher, and I teach high school engineering classes. Our school uses a block schedule, with 3 block periods per day plus a study hall. Most teachers teach 4 classes and have study hall responsibility. I'm one of the teachers who teaches 5 classes, so I have no study hall responsibility in order to provide me with a prep period. My struggle is accommodating students who need additional help. Because I don't have a study hall period, which would be a natural time to help these students, I either help students during my prep period, or refuse to help them; I'm not satisfied with either solution. Further, much of my class is computer-based, and although students can download the software if they have a PC at home, this becomes an equity issue as not all students have computers. I know this is not specifically a Web 2.0 issue, but perhaps there are both procedural solutions and technology solutions. If you have an insight on this conflict, please respond.