There are 893 Silverstars, 893 APC bulbs, as well as 893 PIAA bulbs. All are pretty good bulbs and the PIAA's would be the most reliable at a price. The APC bulb is a good balance between the three in money and performance and can be picked up at many Autoparts stores or Compact Car shops. I know that the local NAPA auto parts store here carries them but I am not sure if they are nationwide.
The absolutely MOST important thing to do is to clean the bulbs with alcohol or the little pad in the bulb package if it has one. If you so much as touch the bulb and get oil from your skin on the glass, you can guarantee that you severly shortened the life of the bulb. If you wanna really do it the smart way then put on a pair of cheap rubber gloves or just clean gloves and also clean the bulbs real well.