Those Ergopower levers you are considering are probably the most extensive/expensive way to modify your bike in the way you desire. Not only would they cost you $110 just for the levers, but you'd also have to buy a new rear wheel, 10-speed cassette, and rear derailleur to work with those levers. And modify the rear frame spacing to fit the new wheel.
Far better, as others suggest, to get either stem mounted or handlebar end shift levers and continue using your current derailleurs and wheels.