I don't think there's any bass until verse 2, in fact I'm not 
sure if I'm just hearing the cello and mistaking it for a bass 
as well for the whole song.  Here is the tab anyway.

Verse 2
|-------------------------------------------------------------------------------|
|-------------------------------------------------------------------------------|
|1----4-------------1----4------------------------1-------------------1----2----|
|----------6------------------6----5----4----1---------6----4----6--------------|

Chorus 2
|---------------------    ----------------------------------------------------|
|---------------------    ----------------------------------------------------|
|-4----6--------------    ----------------------------------------------------|
|-----------8----6---- x3 -4----6----4----1--------4----6----8~---------------|

Bridge
|----------------------------    ------------------------------------|
|----------------------------    ------------------------------------|
|----------6-----------------    ----------6-------------------------|
|-9-----------------8-------- x2 -9-----------------6----------------|

Chorus 3
|---------------------    ------------------------------------------------|
|---------------------    ------------------------------------------------|
|-4----6--------------    ------------------------------------------------|
|-----------8----6---- x3 -4----6----1--------4----6----1--------4--6--8--|

Again, the bass pretty much follows the cello exactly, so it might not
even be a bass, but why not play it anyway?