The upgrade won't necessarily solve the problem. The mechanics of a front derailleur are pretty simple, which is why prebuilt bikes often use a lesser "quality" front derailleur, i.e., a 105 front d/r, while the rest of the components are Ultegra. Take it to your shop, explain the problem and ask them to make sure the front derailleur is adjusted properly. Triples definitely have their advantages, but shifting between chainrings can more trickier. I had problems last year, usually shifting from my little to middle chainring. Since it was tuned up over the winter, however, my shifting has been very smooth.