Were you expecting this low score on the IR or was it a complete shock?
As to the IR importance, we will know in a week or so - there is a GMAC conference and I bet you they will unveil and release the latest IR and Job/GPA/etc correlation scores. Most likely it will say that IR has a strong correlation and most schools will consider the IR scores starting sometime next year but potentially as early as this winter. GMAT Club is attending with 2 moderators coming out, so they will report back.
P.S. To avoid torturing yourself, as a friendly admissions member what they think about the Low IR score. There are a few chats on GMAT Club with adcoms - I think there is one on Wed:
announcement-mba-info-sessions-on-gmatclub-174827.html