I had a room mate who transferred to GT from a community college after a semester with a 4.0 gpa (after doing not so well in high school). He said it's surprisingly easier to transfer into GT than it is getting into GT after high school. Look into it.

GT also has several public events where there are profs / researchers showing their projects which you can attend (especially if you are a student) and possibly even work with them (if you can help with something specific). You should definitely come visit and get to know them. When you apply to get in, having a rapport with a professor goes a very long way to getting in.