I refinanced private loans at 7.8% and fed loans at 6.5% to a variable rate at 4.9% (I bet the Fed would keep rates low, so far that bet has paid off splendidly). They were very helpful through the refinance process and I recommend them to everyone. They are selective about their borrowers, I had a great credit score, so they may require a cosigner.
That said I doubt will be able to do much better than your current terms.