See Sheldon Brown's discussion of tire sizing

http://www.sheldonbrown.com/tire-sizing.html

Lots of confusion in labeling, so read carefully. Actually, it's the number like 622 or 559 that needs to match your rim exactly, whereas a variety of tire widths will fit a given rim, and a variety of tube widths (and even diameters) will fit a given tire.

Tips on changing tires: (1) Don't use tire levers to install the tire. Use your bare hands if at all possible. (2) Be sure to push the pump head straight on and off over the valve. The valve tips on presta valves are easy to damaged. Using a pump with a hose is less likely to cause damage than a frame pump with no hose.