Brake Light Assembly Question

[impboy]

I have a 2001 Boxster and I have a brake light that keeps going out because one end that metal cage looking thing that holds all the bulbs in place pops out just a little bit and the brake light bulb can't make contact to complete the circuit. I can push it back in by hand and it'll stay put for about 5000 miles but then it slowly works itself free and the light goes out again.

Any ideas how to fix it? If it's just best to replace it, what's the part number and where's a good place to get one?

Thanks in advance for any help!