Hi DebWenger,
First off, a 710/Q49 is an outstanding score (it's right around the 90th percentile overall) and it puts you in position to apply to any Business School that you'd like to. So a retake is not required.
In answer to your questions:
1) Many Business Schools have publicly stated that they do NOT use an Applicant's IR score as part of the evaluation process. As such, your IR score is basically a non-factor.
2) A Q49 is a fantastic performance in the Quant - it's a score that most Test Takers will never achieve in their lives. You shouldn't get distracted by the percentile. The percentile for each score level has been slowly dropping over the years. Ten years ago, a Q49 was around the 85th percentile; now, it's right around the 79th/80th percentile. That just means that more Test Takers are scoring at that level (or above). The result is still fantastic though and Business Schools know that.
You mentioned how you were not planning to apply to any Top20 Schools, but you might want to rethink that idea.
GMAT assassins aren't born, they're made,
Rich