Hi whatisthematrix,
The IR Score is scored on a separate Scale (from 1-8) and has NO impact on your Overall Score (out of 800). Many Business Schools have publicly stated that they do not use an applicant's IR score when evaluating an application, so you likely have nothing to be concerned about regarding your performance in this section. As a general rule, I still recommend that you do your best in each section of the GMAT, but you should spend the bulk of your study time on the areas that matter the most (re: the Quant and Verbal sections). In addition, if you're interested in what a specific School/Program thinks about the IR score, then you should research that School (and you might also consider directly contacting the School to ask).
GMAT assassins aren't born, they're made,
Rich