Almost similar. I mean the courses u will be taking and the job u will be working at are the same. The difference is information science specializes on data handling. It breaks it down into the tiniest details and woks on organizing it. Information system on the other hand is all about adminstrating the data. It has also the bussiness side of it. So opt with what u like. GPA it aint need much above 3.0 seems fine but try to do more to be more comfortable.