Here is the tool you need if you want to pull the cranks off the bike yourself and get new ones. There are less expensive ones, but the Park Tool ones work well. You might also need a 14mm socket wrench.

And Here is a crankset that will probably work. A little more searching and you might find one in silver. Or look on Ebay for a "square taper road crankset." My friend recently found very nice one (shimano 600) in a dumpster connected to a Univega frame.