Just on general principal, I'm opposed to refinancing unless it's a reduction of 2% or more. Refinancing your 132K loan, regardless of term, from 5.75 to 4.75, saves you 69.00 per month. If you pay (for example) 1,260 in refinance charges, it will take you 18 months to recoup this in reduced interest payments.
My opinion, unless you find it absolutely necessary to do so, retain your current loan and the 15 year payoff.