this bass part is really simple. the role of the bass in this song is to sort of follow
be the echo of the guitar.im pretty sure this is right and whatever mistakes i may have
im sure you'll be able to figure it out. just play along with the songs a few times and 

Intro: dont play anything

1rst Verse:

G----------------------------------|
D---7-----7-----7-----4-0-----7----|   X2
A---0-----0-----0-------------0----|
E----------------------------------|

second time end on

G----------------------|
D--7777777777777777777-|
A--0000000000000000000-|
E----------------------|

play verse one more time

dont play anything until chorus

Chorus:

G------------------------------------------------------|
D---7------7-----7------4-0-----77777777777777777777---|
A---0------0-----0--------------00000000000000000000---|
E------------------------------------------------------|

The song goes:
 Intro
 Verse
 Intro
 Chorus
 Verse

whatever, you'll figure it all out by listenning to the song a few times, good luck, 
on