'07 Headlight/Ballast Replacement in Minneapolis MN

I have a 2007 Prius and the headlights are working intermittently. They sometimes flicker before going off. This current set of headlights started having problems less than 30k miles after replacement. My last set lasted 40-50k miles. My mechanic (who doesn't work on many Prii) says I probably need to replace the ballast, but he won't do it. Does anyone know of a shop in the greater Minneapolis are that is skilled in fixing Prius headlight problems?