There isn't too much historical data available yet for top bschools to place a heavy emphasis on your IR score. Your score of 5 is considered "good enough" - generally the 5 or 6 range is where you want to be.
The focus is still the 800 score. For top 10-15 bschools, you want to stay above 50% percentile for your IR score as you have done. Just don't slack off and put in a sub-par performance on IR - unless you have a special agreement with your school that specifies you surpass a 650 on your GMAT. In those unique situations, your IR score won't matter.
But for the most part - you got a pretty ideal score. Great score and just good enough IR - that's exactly where you want to be. Congrats!
For more info on Integrated Reasoning, please see the FAQ here: http://www.gmatpill.com/gmat-practice-t ... -reasoning
... and more
What's Inside GMAT Pill?
Zeke Lee, GMAT Pill Study Method (Study Less. Score More.)
GMAT Pill Reviews | GMAT PILL Free Practice Test