Using an h-bridge can improve haptic performance (reversing the polarity stops the motor quicker), but as Riva mentioned there's no need if your doing simple vibration alerting. Tonnes of advice from the motor's manufacturer:
Discrete driver circuit
H-bridge
Integrated driver circuit
You can buy MOSFETs from tonnes of electronics shops (depending on your location), e.g. Maplin, Farnell / Element14, RS online, Radioshack. It's also worth checking Ebay, lots of sellers specialising in hobbyist electronics. For the h-bridge you can either build yourself out of transistors (actually a pretty simple build, the schematic looks way more complicated than it is), or buy an h-bridge chip.