Love my Specialized Ruby Pro 2007. But need a few more "clicks" to get me up many of the hills I ride on in western PA. I seem to run out of gears climbing up hills. Thinking of changing out my compact double 50 - 34 with 12-27 for either an 11-28 or changing just the rear derailleur to a mountain bike one with a 32, 34, or 36 in the back. Please give me a bit of advice.