where to buy best torx screw driver for changing headlamps ?

[diegoA4]

Changing the headlamps on the A4 is a nightmare.

I dropped my torx screw driver tip and its gone for good until it rattles out onto the street while changing the right headlamp.

So I need to find a decent tool for unscrewing the bloody torx screws holding the headlamps in place.

What's the best tool for the job? Where do I buy it? Can I buy it on line? Uggg. This is so frustrating.