This is what bass would play along with a guitar if you might (possibly) be playing with a guitar.

G |------------------------|
D |------------------------|
A |------------------------|
E |5~----3~----1~----0~----| 4x

G |------------------------|
D |7~----------------------|
A |------7~----5~----------|
E |------------------8--555| 2x

G |------------------------|
D |------575~--------575~--|
A |---578----8~---578----8~|
E |578---------578---------| 2x

those are basically the three parts to the song. mix and match as you like. 


ENDING
G |--------------------------------|
D |10---9-10-----7~~~--------------|
A |--------------------------------|
E |--------------------------5~~~~~|

really hit that low A, makes it sounds coo.