That Fuji is a good bike--I would get a nice, inexpensive bar (maybe even a flat bar like your mountain bike) that fits your width, and the rear brake the others mention. Then just ride it! Single speeds are all the rage right now (especially downtown Los Angeles, where I work), and your Fuji is actually "cool" again. I'm seeing a bunch of cool looking old-school bikes being brought out, dusted off, converted to single speeds, and ridden hard! Most importantly, have fun!