If you truly have an inside-out swing, you are in the money already. Many minor league hitting instructors earn their pay by teaching ballplayers, who are getting huge signing bonuses, how to swing inside-out.
You're already there. The inside-out swing helps you to hit behind the runner (if right handed), allows you to wait longer on that inside pitch, and develop power to the opposite field. This is a good thing.
If you're having problems hitting, go see a pro who can teach you how to put that solid gold swing to the proper use. He can teach you how to turn on an inside pitch to pull it while still keeping that oppo swing intact.
Edgar Martinez, Alex Rodriguez, Alex Rios all have inside-outters (Rodriguez is now more of a pull-hitter since he decided to emphasize his power).
All in all, its a good place to start.