Hey guys,
My current rig is a Fender Deluxe P-bass Special 4-string
and a
Berhinger Ultrabass BXL 1800A

I realize this amp isn't so great, but I was on a budget. Anyway, I'm just not getting the sound i want out of this setup. So, I was wondering if anyone knew of any pedals or pickups i could use to get the sound i want. The sound i want is a Mike Dirnt from Green Day type sound. I play mostly punk music and some alternative etc. So I'm pretty much just looking for a good punchy distortion sound. thanks in advance.

as you can see, Mike plays a P-Bass through a Fender rig. I'd say its definitely your amp, because you have a P-Bas which makes half the equation. Also, you get try getting a distortion pedal like the Big Muff or the Boss ODB3 Overdrive. Both could help you add some grit to your tone.
Sansamp Bass Driver DI!!! that will add either a little or a lot of grit and can add alot of different tonal options and has many different uses. go look it up
ESP B-405,Fender American Jazz Bass(EMG J active pups and LEO QUAN BADASS II ) squire P bass(EMG P active Pups)),
SansAmp Bass driver DI
Ampeg SvP PRO Tube Preamp
QSC2450 Power amp
Furman PL8